The Comprehensive Guide To Rat Grease Marks

There are many signs of rat infestation. And one of them is the smear marks, also known as rat grease marks.

When there’s a rat infestation in a home, many homeowners fail to recognize the rat grease marks as the sign.

They think it’s just another dirt mark. 

The possible end result?

Rat infestation and the damages by rats inside the home rise.

And not to mention the health risks you face when there are a bunch of filthy rats and rodents in your home.

In this guide, you’ll find out how to recognize rat grease marks and in what places you’re more likely to find them.

You’ll also find out what are the six signs of rat infestation in your home that guarantee rats’ presence in your home.

And a lot more! Keep reading

What Are Rat Grease Marks?

Rat grease marks are smear marks that rats leave behind when they crawl. These smear marks are the deposits of the filth, dirt, and oily substances that are on the rats’ bodies.

Rat Grease Marks

Outside your home, rats live in the filthiest places that you can ever think of. From garbage cans to city sewer lines, rats inhabit those dirty, damp, and dark places.

Hence the dirty and oily greases are always present on the rats’ bodies, paws, and fur.

So, wherever rats crawl, the dirt and filth will stick on the hard surfaces in the form of smear marks.

Rats also have a habit of rubbing themselves on hard objects. That also leads to the rat smear marks.

Rat grease marks are one of the signs of rats in your home. And like the rats, mice also leave behind grease or smear marks.

There are other signs of rats in the home, which you’ll find out in a minute, but for now, let’s find out what rat grease marks look like.

What Do Rat Grease Marks Look Like?

Rat grease marks look like dab or smears that are black in color. These marks are dark at the beginning, and they fade away a bit at the tail end.

Rat grease marks look like dab or smears that are blackish. These marks are dark and broad to begin with. They thin out like a tail end.

Around the rat smear marks you’d also notice the rat’s paw marks and tail drag marks from the rat grease marks.

Some of the grease marks also have a light yellowish dab around the smear marks. That yellowish deposit is rat’s urine.

Rat’s urine is blueish when it’s fresh and yellowish when it’s stale.

Rats also have a habit of defecating and urinating inside the home randomly.

If there’s a rat hiding in your home, then you’ll find rat feces and rat grease marks with traces of urine in your home too.

So, your obvious question right now is where do you find rat smear marks inside your home?

Let’s find it out.

Where Do Rats Leave Smear Marks In Your Home?

There are three common places where you’ll come across rat smear marks. These are the places where rats hide, on the commuting route of the rat, and at the damp places.

And where do rats hide?

Rats, and most rodents like mice and squirrel, hide in cluttered, dark, dirty, and damp places inside your home.

So, places like crawlspaces, attics, basements, storage rooms, bathroom, kitchen, vents, and ducts are the places where rats hide and take shelter.

In the worst case scenario, rats and mice can also hide in your bedroom too. In your bedroom they can hide in closets, wardrobes, and inside dresser drawers. 

And it’s on these places where you’ll come across rat grease marks.

You’ll find rat smear marks on the baseboards, beams, boxes, and on the floors too. These smear marks indicate that the rat has been using this route to go from one place to another.

Doing so, it’s leaving the marks behind.

As rats leave behind the grease marks when they rub themselves on hard objects, so many people call the smear marks as rat rub marks.

The rubbing of their bodies on the hard surfaces causes the dirt and semi-liquid gluey filth on their bodies to stick on the hard surfaces in the form of dabs and smears.

Rats also use little holes as their entrance points in your home. They can crawl through holes which are as tiny as half-an-inch in diameter.

These holes will also have rat smear marks because the oily dirty will stick on the holes. Over time, when the rat grease marks turn stale, they turn black.

From the grease marks, you’ll also notice paw marks and tail drags. 

Pest controllers use the rat grease marks and paw marks on the dust around the smear marks as a trail to find rat’s nest and hiding places.

That helps them to locate the rat’s nest or lay rat traps.

Apart from rat grease marks, there are other signs of a rat infestation in your home.

The following section reveals all the signs of rats infestation in your home.

6 Signs Of Rat Infestation Inside Your Home

Rat gnaw marks, rat grease marks, rat poop or droppings, rat urine, burrows, rat nests, and excited pets in your home are the six signs of rats infestation in your home.

Let’s have a look at each of them.

#1-Rat Gnaw Marks

Rat gnaw marks

Rat gnaw marks are rat’s teeth marks on the things that they’ve chewed. Rats’ teeth are always growing, and they’ve got a habit of chewing on things. Consider it as a rat’s favorite activity to pass their time.

When there are rats in your home, coming across the gnaw marks is pretty common.

You’ll find the gnaw marks on many things like cardboard, books, furniture, carpets, floors, and even on wires and electrical outlets.

Rats are infamous for damaging many expensive products like memorabilia and home décor made out of feathers, shoes, souvenirs, and even picture frames.

The rat gnaws marks have rough edges, and it’ll appear as if someone has taken a bite at the thing.

Your kitchen and food pantry is the food source for the rats hiding in your home.

So, the gnaw marks can also appear on food storage jars and packets.

When rats and mice gnaw, you’ll hear a chewing sound. Rats are nocturnal, so you’ll hear the chewing sounds at night or early in the morning.

This chewing sound is not at all good for your home.

It’s because it can indicate that there’s not only a possibility of rat infestation but also termite or roach infestation in your home.

So, if you hear any chewing sounds, then it’s a menacing sign of pest invasion on your home.

#2-Rat Droppings

Rat droppings

Rat droppings look like crescent-shaped shiny black seeds, that can be 3/4th of an inch long. When fresh, rat droppings have a black sheen on them. 

Rat droppings are thicker and bigger than mouse droppings. But the color and the shape is similar.

When the droppings become stale, they turn dry, greyish, and they lose their shine too.

Rats have a habit of defecating at random places in your home. But there are certain places where you’re more likely to find rat droppings if there are rats in your home.

These places are crawl spaces, attic, underneath furniture, inside kitchen cabinets, behind utensils in your kitchen shelves, and even in the food pantry.

Rats will defecate in tight corners and places where they can fit in.

Rat droppings do not have any white tip on them. If there’s a white ending on the dropping, then it can be a lizard dropping.

What to do if you see rat droppings? No matter what you do, don’t touch it with bare hands.

Take a broom and sweep it off the floor if the dropping is dry. You can use a vacuum cleaner to remove the dry rat droppings.

If it’s wet and fresh, then it would be best if you scoop it off with a cardboard piece.

Wear a pair of gloves while doing it. And once you discard the dropping, ensure that you wash the place with a disinfectant.

#3-Rat Urine

You’ll also find rat urine in places where you found rat droppings. The surface where rats urinate turns yellowish when the urine dries up. 

Fresh rat urine is bluish.

Rat droppings don’t emit a smell, but rat urine stinks. Rat urine will emit a pungent and musky odor like ammonia.

It’s common to find rat urine traces around the rat smear marks. Rats can urinate while they’re rubbing themselves against a hard object.


Burrows are a sign of rat infestation that is hard to find inside your home. But if there are rats in your property, then you’ll indeed see burrows in your yard or garden.

Rats dig burrows not only to hide but also to build their nest.

Sometimes these burrows can be interlinked with underground tunnels that rats will use to commute from one place to another.

The burrows also play an important role in keeping their newborns safe from potential predators.

But many homeowners have noticed rat burrows inside their homes too. 

Roof rats make these burrows on damaged roofs, eaves, shingles, and even inside damaged walls.

Roof rats are pretty common in Texas

Another species of rats that are common are the Norway rats.

Norway rats are bigger than roof rats. Pest control professionals can recognize if it’s a Norway rat or roof rat in your home by looking at the feces.

Norway rats’ droppings are bigger than roof rats’ droppings. The average size of a Norway rats’ poop is 1/2 an inch.

Roof rats enter homes from higher places, and they tend to hide and build their nests near the roof and ceilings.

#5-Rat Nests

And finally, if there’s any sign of rats in your home that tells that rats are inside for sure, it’s the rat nests.

The most common places where rats will build their nests inside a home are attics, crawlspaces, in the walls, and in cluttered places of your home that you don’t visit often. 

So, places like the basement are also one of the places where rats can build their nests.

Rats build their nests with soft materials like fabric and plant matter. They’re more likely to build a nest in a dark place and don’t receive much light.

Outdoors, in your yard, the holes or the burrows that you’ll notice are possible rat nests, especially when the holes don’t have any debris or webs. 

#6 – Excited Pets Looking For Something In Your Home

When there are rodents of any type in your home, your pets can pick their presence fast. 

Notice your pet’s activities. 

Is your pet acting too excited and nosy? Is your pet always searching something in nooks and corners of your home?

If yes, then there are chances that your pet has spotted signs of rodent activity in your home.

What To Do If You Find Rat Grease Marks And Rat Feces In Your Home?

Greasy rub marks of rats and rat feces are a sure sign of rats’ presence in your home. 

In all honesty, getting rid of rats is a tricky job and it’d be best if you hire a pest controller to do the job. 

But there are certain things that you can do to ensure that rats don’t enter the important areas of your home, like your bedroom.

And stop more rats from entering your home. Let’s find them out.

Seal Holes And Cracks That Can Let Rats Inside Your Home

As you know, rats can use tiny holes and vents as entrance points to your home.

Seal those holes and gaps. Ensure that you use silicone-based sealants to do the job.

Silicone-based sealants are sturdy and rats and bugs can’t chew through them. Sealing the holes is the primary technique to prevent rodent infestation in homes.

If there are wall voids the cement those voids. Rats, and especially mice can also hide in these voids.

Ensure That Trash Bins Are Empty And Are Always Covered By A Lid

Rats and mice feast on the food waste that you dump in the trash bins both inside and outside of your home.

Do not let the food wastes lie in the garbage bins for days. Regularly dump your trash and keep your trash bins clean.

And the most important thing is that all of the trash bins should be covered by a lid. 

Open trash bins emits smell that rodents can pick up which leads them to your home and property.

Keep Your Yard And Garden Clean To Prevent Rats From Nesting In Your Outdoors

Rats make nests in burrows that they dig in your yard especially when your yard is full of organic and food waste. 

So, keeping your yard clean, grasses and shrubs trimmed, not overwatering your yard, and keeping mulch beds away from the homes’ foundation help a lot to keep rats away from your property.

Scatter Talcum Powder Or Flour On Places Where You Suspect Rats Crawl

Things like talcum powder, flour, and cornstarch on specific places like near baseboards, and underneath furniture are a great way to detect rat activity.

If rats use these places to commute, then there will be rat paw marks on the powder. 

That’ll help you to lay rat snap traps in those areas. Believe it or not, rat snap traps are tried-and-tested method to eliminate rats from homes.

You can also keep the rat snap traps in places like attics and basements where rats commonly hide.

Spray Peppermint Essential Oil In Places Where Rats Can Hide

Rats hate the smell of peppermint oil. It repels rats. 

Spray peppermint oil in the hiding places of rats. If you’ve noticed burrows in your yard, then spraying the peppermint oil in the yard will also keep rats away.

Presence of multiple rats in home can trigger allergic reactions in sensitive people.

And rat feces carry many harmful bacteria that cause diseases like salmonella and Hantavirus.

On noticing rat smear marks, implement these steps and hire a pest controller asap.

How To Clean Rat Grease Marks?

If you’ve found rat grease marks, then you should clean them. It’ll be best if you clean it with a disinfectant.

CDC or center of disease control also recommends spraying a mixture of bleach and water ( one and a half cups of bleach with a gallon of water) on the surface where you saw the grease marks.

Spray the mixture on the surface with grease marks and let it sit for 10-15 minutes. Then wipe off the surface with a disinfectant cloth.

Clean the place nearby. Ensure that you remove clutter in the hiding places rats such as attics. 

If there’s a damage in the insulation that many rats cause, replace the insulation. 

While cleaning the rat grease marks please wear a mask and pair of gloves. You shouldn’t inhale the dust and the stench while cleaning the rat rub marks. 


Rat grease marks are a clear sign of the presence of rats inside your home. 

In this guide, you’ve found out what do rat grease marks look like and what you need to do to get rid of those grease marks. 

Plus, there’s also a list of six signs of rat infestation on top of the rat grease marks. These signs are a tell-tale sign of rats’ presence inside your home.

To get rid of rats, it’s always wise to hire a pest controller to do the job. These rats can also bring along rat mites with them, which are human biting mites.

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