Written by Laurie Goldstein, November 2011
Recommendations for home-made formulas to clean cat urine stains are widely circulated on the Internet, and typically include some combination of vinegar, hydrogen peroxide and baking soda. Of course, many people unfamiliar with the problem of cleaning cat urine stains simply try to clean up cat pee as they would any other stain, only to find out later it didn’t work. In fact, using traditional household cleaners on cat urine actually “sets” the stain. This makes the stain even more difficult to remove with proper enzyme cleaners.
There is a strong, legitimate, and chemically important reason to use an enzyme cleaner to clean cat urine stains. Home-made mixtures or typical household cleaners simply do not contain the required ingredients to remove ALL the components of cat urine. Vinegar and baking soda work to neutralize the odor temporarily, and hydrogen peroxide is 30% more oxidizing than chlorine. But cat urine is composed of things that REQUIRE enzymes to break down the chemical bonds.
Cat urine is composed of:
• Urea
• Urobilin/Urobilinogin
• Uric Acid
• Sodium
• Other electrolytes
• Creatinine
• Pheromones
• Bacteria – typically 5 different strains.
When cat urine dries, the urea is broken down by the bacteria. This is what makes it smell like ammonia. As it decomposes further, it releases thiols that make the odor worse. (It is the thiols in skunk spray that make it SO potent and difficult to remove).
The urea and urobilin/urobilinogin are not hard to clean. Urea, urobilin/urobilinogin, creatinine and the pheromones are water soluble (urobilin is the pigment that causes the color). Traditional household or carpet cleaners will deal with these, and this is why hydrogen peroxide, vinegar, and/or baking soda also appear (initially) to be effective at eliminating the problem. But the problem has not been solved! Uric acid and its salts have been left behind. Uric acid is not water soluble and bonds tightly to whatever surface it touches.
Due to the uric acid component of cat urine, cat pee has a half-life of six years.
This is why it is absolutely essential to use a cleaner that can break down the uric acid. Soap, vinegar, baking soda, ammonia, chlorine, and hydrogen peroxide (to name the most common cleaners) simply are not chemically capable of breaking down the uric acid in cat pee. These cleaners and deodorizers only temporarily make the smell go away and appear to work because they do clean up the other components of the cat urine. But when exposed to humidity, the uric acid salts cause the uric acid crystals to reform. This process releases the smell again; not always at levels detectable to the human nose, but the cats’ more sensitive noses can smell it. And the scent of their urine outside of the litter box encourages many cats to continue urinating outside of the box, often with their families left scratching their heads wondering why.
The only thing that will break down the uric acid to permanently remove the smell is an enzyme cleaner. The enzymes break down uric acid into carbon dioxide and ammonia, both gasses that then easily evaporate. This is why it is also essential to allow the enzyme cleaner to air dry. It needs the “natural” drying time to break down the uric acid salts, allowing the resulting gases to evaporate.
Not all enzyme cleaners are equally effective. Good enzyme cleaners are typically a bit more expensive. Cheap ones will work, but need to be reapplied over and over (and probably end up costing as much as the more expensive enzyme cleaners). Enzyme cleaners this author is aware of that work well and reliably include Nok Out, Urine Off, and Anti-Icky Poo.
Of course any cleaner needs to be used properly. Most enzyme cleaners come in a spray bottle. This is deceptive, because just spraying a light layer of enzyme cleaner over a urine stain will not result in complete cleaning of that spot. Cat pee wicks, and unless the enzyme cleaner completely envelopes all of the cat pee, even it won’t work. “Spraying” doesn’t work. Dousing, pouring, and soaking are required when cleaning up cat urine.
To properly use an enzyme cleaner on a fresh stain:
1. Blot up as much of the urine as you can before applying anything.
2. Soak the affected area with the enzyme cleaner.
3. Let the enzyme cleaner sit for 10 to 15 minutes.
4. Blot up as much of the enzyme cleaner as possible.
5. Leave the enzyme cleaner to air dry.
Covering the area loosely with something is always a good idea. This will not only help prevent the cat from attempting to pee on the same spot while the enzyme cleaner does its work; it will stop family members from stepping or sitting on the wet spot. Some people lay aluminum foil down over the area; other recommendations include an upside down laundry basket or an aluminum baking sheet.
The same basic procedures apply for an old stain. But be aware that an old stain may require two or three full cycles of enzyme cleaner application (allowing it to completely dry between applications) in order to completely clean the stain.
Cushions and mattresses can be cleaned! Soak the affected area of the cushion. As mentioned earlier, cat pee wicks, and you must get the enzyme cleaner to wick to all of the same places the cat pee did or it won’t work. If possible, take the cushion outside, blot up as much of the cat urine as possible, then soak the cushion by very slowly pouring the enzyme cleaner on/around the affected area, giving it time to really soak through the cushion. Let it sit for 15 minutes then squish out as much of the excess enzyme cleaner as possible. Finally, blot up what you can (with a lot of towels). If sunny, leave the cushion outside as long as possible while it dries. To continue using your couch for the days it will take your cushion to completely dry, lay aluminum foil down over the couch, put the cushion down, put another layer of aluminum foil over the top of the cushion, and a throw blanket on that. When you’re done for the day, remove the throw blanket leaving the aluminum foil behind to discourage kitty from peeing on it while it completes the drying process. When dry, the smell of cat pee will no longer tempt kitty to pee on the couch.
To treat a mattress, use essentially the same process as for the couch cushion (you don’t need to remove the mattress from the bed!). Slowly pour the enzyme cleaner on/around the affected area, ensuring it has the chance to really soak in thoroughly. Let it sit for 15 minutes, and then blot up what you can with a lot of towels. Place several layers of clean towels over the area, and then make the bed. Just swap out those clean towels each day (if done properly it will take days to dry). To discourage peeing on the spot while the mattress dries, cover the bed with a large plastic sheet or tarp when you’re not using it, or take a large box, cut it down, and lay it over the top of the bed when you’re not using it.
Thick cushions and mattresses may require several applications to completely remove the cat urine. The thickness is the issue, and getting the enzyme cleaner to all the same spots the cat pee went is more difficult on the thick things. But rest assured, your couch or your mattress is not ruined if your cat pees on it. You will be able to clean it!
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Created 04/27/13; Updated 08/11/14
