Cool stuff. My buddy has a trick where he throws the expanded coco into a large volume of water, then (fairly rapidly) scoops out the good coarse stuff which floats on top. It gets rid of all the fine particles and dirt/nails/horseshoes/tiger teeth/golf balls/rocks. Only thing is, there goes like 1/3 of your coco. It's still good to chuck on the veggie garden or compost heap though.