Like stated, you can buy it already clean. But if you want to make sure or get "un clean sand" you can do this.. I did/do this for my fish tanks. Get two buckets. Fill about 1/4 of the way with sand then fill 1/2 with water and swoosh it around, drain water and repeat 10 or 15 times. Dump into another bucket, then repeat. Of course that's for aquariums. You could prop swoosh it around less for chams...