This stuff is great, in fact I've ordered another quart. I had an old, old stain that nothing had worked on. We could get it looking reasonably good but the stain would come back in a few days. Obviously, it was many layers deep. Though it took several daily applications, My Pet Peed has virtually eliminated the stain. I decided to let it set a few days to see if it would come back like always before, but it has not. I'm going to try more daily applications as necessary in hopes to eliminate it for good!