Cats that do not use their litter box pose a difficult problem for their owners. These people may be torn and unsure of what actions to take: after all, they love their pet, but they just can't stand living in a house that reeks of cat urine. This stain is difficult to remove, but the following tips have proven helpful in most situations.

1. Find the stain. This can be relatively easy if the urine is wet, but if the stain is dry, you may have to get down on your knees and literally sniff out the source. A black light is an investment that can make this easier, because stains will glow underneath it.

2. Do not rub; blot. If you rub a urine stain, you will only spread the stain. Instead, use paper towels or a clean, absorbent cloth to sop up the wet stain.

3. Use weight. Place dry paper towels on top of the wet stain and stand on top of the stack for at least 30 seconds. Your added weight will apply more pressure and soak up more urine faster. If the stain is dry, just use some water to get it wet again, and follow the process above.

4. Rinse the stain. Use warm water to rinse the stain and blot with a clean cloth. Again, cover the stain with paper towels and stand on them for at least 30 seconds. This will ensure that you soak up and remove as much urine as possible before using an enzyme cleaning product.

5. Use an enzyme cleaner. Make sure to use a product that has "enzyme" or "enzymatic" on its label. Many cleaners have fragrances or cleaners that make the odors undetectable to humans, but your pets have a better sense of smell and will still be able to smell the urine. Enzymes actually consume the odor particles instead of just covering them. Some good product choices are Urine Off (which includes a black light) and Nature's Miracle. Make sure to test a small, covered area of the carpet or upholstery to be cleaned before you apply large amounts of these cleaners.

6. Cover the stain. After applying the enzyme cleaner, cover the area with foil. These cleaners take some time to work, and they are most effective when the area is saturated and covered. Make sure to follow all instructions on the label.

7. Use Feliway. This product mimics feline facial pheromones, which are natural substances cats use to communicate. Feliway can be purchased as a diffuser or a spray, and it may help calm a stressed cat. This is effective because stress is what causes many cats to urinate outside their litter boxes.

8. Don't use carpet shampoo. Using a traditional detergent like this may actually work against the enzymatic cleaner and make it ineffective. Wait until after the urine stain is gone to clean your carpets. No matter how tempting it is to rent a carpet shampooer, but steam-cleaning may actually exacerbate the odor problem. (Steam and heat, when coupled with an already bad smell, do not get along very well.)

9. Other tips. Avoid cleaners that are ammonia-based. Because ammonia smells like cat urine, cleaning stains with these products may actually attract your pet back to the same spot. A good alternative is a citrus-scented cleaner, because cats hate the way they smell.

Remember: a cat that stops using its litter box may have a more serious medical problem. You should contact your veterinarian if you have any concerns.