I always rinse my new Charcoal out alot under cold running water but it seems like no matter how much I rinse it out it still always has some black dust that I can't get rid of, I mean I rinse it out for sometimes 15 minutes and there is always more black dust that I could rinse out if I wanted too. I don't think I can get it any cleaner unless I wanted to stand there and do it for an hour or two. Is it clean enough and activated enough after 10 or 15 minutes or so.