This summer I rinsed and dried about 20 lbs of 2mm sand that I had in my tank before I moved. I left the nice, clean white sand in a rubber maid tub in my tool shed with out the lid on. I recently noticed that my cat has decided that the tub should be used as cat box. Grrrrr. So the question is, is the sand garabage or can thorough rinse and clean the sand again for later use?