i dont use the product anymore but i can say that yes you can "rinse" the product. im not sure you can "wash" it though. if your just trying to re-juvinate its looks and wash away dust then i would say yes you are fine with doing so. if you are actually trying to re-use soiled pooped on urate filled stuff than i would say no. throw it away and buy new.
i used to rinse new stuff in a colander and then lay it out on an old screen in the sun to dry just to remove dust from the product. ive never tried washing it. i would advise against it.
adam jeffery