This is a toughie, cat urine is almost impossible to completely get out. Try the Nature's Miracle, a gallon will last years, and then set the cushion outside in some sunlight and fresh air for as long as you can.
Good luck!
By
03/10/2011
Vinegar! Pour it on, let it dry. Will be all gone.
By
03/09/2011
There is a product called "Nature's Miracle" (you can get it at pet stores) that you put on and let it dry, and it is supposed to get any pet odor out. It has a great reputation, though I have never used it. If you cannot wash the cushion, this might be an option.