Rat Grease Marks – The #1 Sign Of Rat Infestation That You Can Ignore

In this guide, you’ll find out what rat grease marks are, why rats leave grease marks behind, and where.

You’ll also learn what to do without putting yourself in danger if you come across rat grease marks in your home.

So, from the time you finish reading this post, you’ll be able to ascertain the presence of rats in your home like a pro.

You won’t disregard the smear marks as regular deposit of dirt.

Let’s dive in.

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 bins to city sewer lines, rats inhabit those dirty, damp, and dark places.

Living there causes the dirty, oily greases to stick on the rats’ bodies. And when they sneak into clean places like your home, the grease marks stick on hard surfaces.

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.

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.

Rats also have a habit of defecating and urinating inside the home randomly. So, finding rat poop and spots of rat urine in random places inside your home and around the smear marks is standard.

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

And where would you find rat smear marks in your home? Let’s check it out.

Where Do Rats Leave Smear Marks In Your Home?

Though rats can leave grease marks at random places in your home, there are certain places where these grease marks are pretty easy to find.

And these places are where rats hide or use as entry points to your home.

Crawl spaces, attics, basements, tight corners in your home, behind fixed storage places like bathroom vanities and kitchen cabinets, on the vents of utility wires, floors, and baseboards are some of the places where you’ll notice rat grease marks.

Rats have a habit of rubbing their bodies on hard surfaces, and that’s why rat grease marks are also known 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. 

You can also find rat grease marks in areas of your home that are pretty damp.

So, any plumbing area in your bathroom, kitchen, and basement can also have rat grease marks. 

Also, rats can sneak inside your home from little holes which are not more than half an inch in diameter. These holes get blackened by the rat grease marks.

Fresh grease marks are wet, but with time the grease marks dry. You’ll also notice rat paw marks and tail drags around the grease marks. 

But there’s one thing that these smear marks tell you, which can be to your advantage, especially when you try to get rid of rats in your home.

Rats leave behind smear marks on places from where they commute often. 

So, these marks are also a sign that tells you that rats use these routes either to reach their nests or their food source.

Pest controllers use the rat grease marks as a trail leading to the rat’s nest or hiding place. 

That helps them to eliminate the rat infestation.

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

So, what are they? 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, and rat nests are the six signs of rats infestation in your home.

Let’s have a look at each of them. We’ll skip the rat grease marks in this section as we covered the topic in the previous sections.

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.

Rat gnaw marks

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.

Rat Droppings

Rat droppings look like black seeds, and they can be 3/4th of an inch long. When fresh, rat droppings have a black sheen on them. 

Rat droppings

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. 

Rat Urine

You’ll find rat urine in places similar to the 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 smell like ammonia. 

If you see rat urine traces, clean the surface with a disinfectant. If it’s not a wooden surface, you can also use a bit of bleach to clean it.


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

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

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. 

What To Do If You Find Signs Of Rat Infestation In Your Home?

In all honesty, getting rid of rats can be tricky, and you’ll need professional help. 

To eliminate rats from your home, 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.

Using essential oil sprays is one of them, and it’s proven to be effective in repelling rats. You can use peppermint or eucalyptus essential oils to secure your bedroom and other rooms of your home.

Rats hate the smell of peppermint and eucalyptus. Mix peppermint essential oil with water and spray it in your rooms every day.

That’ll stop the rats from entering your home. 

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 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.


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.