To remove a urine smell from the carpet try this. 2 tablespoons of baking soda and 16 oz of hydrogen peroxide plus a squirt of liquid hand soap. Mix together and pour on the stain let it dry and the smell is gone. It may cause a slight bleaching of carpet, but I haven't noticed much of one. I swear by this stuff, I had several cat/dog pee stains on my carpet and the smell was awful. I had to treat it a few times but it worked. Don't put this in a closed bottle though because the peroxide and baking soda could cause a closed container to explode.