I own the Silk Small by Tantus. According to the listing on this site, they are boilable. But up until this point I have just cleaned it with dishsoap and hot water. But I figured I should try boiling it. So after my my last session, I cleaned it like I normally do, then threw it in a pot of water, and boiled it for about 10-15 minutes. When I dumped out the water, the pan was covered in a powdery white residue. Should I be worried?