The furry friends that share our houses bring something special to our lives. With silly antics, undemanding affection and loyalty, pets offer something that can't be found anywhere else. Sharing our homes the way they do, it's inevitable that they'll also contribute to the wear and tear on a home. Dirty paws, upset stomachs and house-training accidents are part of the process of having pets, but they don't have to be permanent marks in the home.
Common Pet Stains

Dirt
One of the most common stains that pets contribute to is simple dirt. Pets don't stop to wipe their paws like humans do their feet, but mud isn't prone to leaving permanent smells, so it's a simple matter to address. Clean up loose dirt and blot any wet spots with an absorbent cloth. Cover the stains thoroughly and allow a general cleaner to work for a minimum of five minutes. Blot up the excess cleaner with a clean, absorbent cloth and allow it to dry before vacuuming. It's a good idea to keep pets and children away from those areas until the final vacuuming step is done so there's no chance of exposure to potentially harmful chemicals.
A tip for keeping inquisitive noses and curious fingers from the spot is to turn an empty laundry basket over the area and set a few books on top to keep it weighed down. This will allow air to circulate to the drying carpet while preventing any close encounters.

Pet Urine
Pet urine is the second most common pet stain, and anyone who's been training a puppy or owns a small toy dog is aware that accidents just happen. Cats that haven't been fixed can also be the victim of their instincts and mark their territory with urine.
The problem with pet urine stains is that they affect all layers of the carpet. The stain on the surface of the carpet is just a small portion of the problem. As the urine soaks down the carpet fibers and into the pad, it spreads out and creates urine crystals that hold that "pee smell" for years. The odor from a pet stain will linger if the whole stain, including what is in the pad, is not removed.
If not treated properly, the odor from pet accidents can travel through the entire home and impact your health. So for pet urine stains, a professional carpet cleaning that specializes in pet urine removal treatment is likely your best bet to eliminate the stains and odors entirely. Chem-Dry, for instance, has a revolutionary process for removing pet urine that eliminates the crystals and stops odor from spreading. They can also include upholstery cleaning in the service as accidents don't always happen on the floor. Calling in professional carpet cleaners such as Chem-Dry at least once a year is a preventative measure for a pet-owning household because standard housecleaning can't reach all the areas that urine stains may be affecting.

source https://www.chemdry.com/blog/pet-stain-removal-tips