I was asking for technical help on RinkWorks the other day. I was trying to clean out a motor scooter gas tank. It was full of crude that developed over years of just sitting.

LaZorra suggested acetone, which I thought I had in the garage. It turned out to be lacquer thinner, but that worked pretty well. I put in a few ounces, swish it around and out comes something that looks like chocolate syrup, and smells like a chemical plant. If I keep doing that long enough, I might get it clean enough to use. This is a great handy-helper site.
Howard