Club soda is the best stain and odor remover I've found when my dog has a potty accident on the carpet. The key is to get to it as soon as possible. First use a paper towel to tab up as much of the urine as possible, then pour about 1/2 a small bottle of club soda directly on the area. Watch it fizz, wait about 5 minutes, and then dab it again with more paper towels. You will not see or smell any evidence as long as the stain hasn't had time to set in.
That sounds great, but I recently bought a used off-white upholstered chair that had a few 'spots' on it, and my daughter's dog has added to these spots. Needless to say, they are not new stains. The fabric is 100% heavy cotton. Any help?