I just bought a really nice black standing picture holder from GoodWill and it looked as though it was never opened. When I got it home and took it out of the box it appeared to have a wet stain on it that smells like urine. I don't know what from but it appears now that someone packed it up very nicely and dropped it off. I got it for a great deal, it is nice but i need to know if or how to get rid of the smell. What kind of product can I use.