In the past 2 years I've sent about a hundred coins to Anacs. All type coins and most Unc 60 or better. I do not like toned coins so I sent a couple test coins to them that I had quickly dipped. They came back without detection. I ended up sending all my slightly toned coins after dipping them and not one came back as cleaned, and some of them are quite valuable. Obviously I concluded they do not know the difference. Heavily toned coins ( I like to call them rusty ) will show missing detail if dipped because it will take off the oxidized portion of the coin's details. These will probably be graded as cleaned. Otherwise I would never clean coins of any kind.