Removing set-in pet stains can be challenging. It's always best to catch pet and other stains as soon as the stain occurs if possible. But if a stain is located in an out of the way place, or if you move into a home with stained carpets, you may need to treat an old, dried stain. A few simple household items will help to remove even old pet stains.
Spray the stain with a solution of one cup of water with one tablespoon of vinegar. Blot moisture with paper towel.
Work a solution of one quart of water and 1/4 teaspoon of dishwashing detergent into the stain.
Rinse with tap water in a spray bottle or on a clean white cloth.
Cover with several layers of paper towels and a weight and allow to remain overnight.
If any stain remains, apply three percent peroxide solution and leave undisturbed for one hour.