Some folks say not to use it because it is full of waste. I say rinse it very well in tap water. Save a few cups of it and rinse the rest until very clean. I mean, and I've said this before, SAND does not go bad. Once you remove the particulate matter then it is clean sand again. Put it in the tank with a touch of chlorine remover and then add the few cups that you saved to "seed" the sand bed with microfauna again.
Here in Austin we are very earth friendly. Nobody just tosses out old aragonite around here. We may remove it from a tank and put the bucket on the back porch, but it will always end back up in somebody elses tank. I see buckets traded back and forth all the time.