I've been negligent and have too much cake build up in many of my bowls. I've read people use some fine sand paper sometimes wrapped around a dowel, to remove excess cake from the bowls, but with most of them the bowl is too small to really get a finger in there, or to get enough leverage on a dowel. I really don't know what to do. It really does have me sort of worried that I've ruined them. I have a couple of those cheap reamers, but those things break easily! Help! I'm actually thinking of sending some to someone for a pro-cleaning! Do people do that? About how much does that cost per pipe?