When I am going to silver solder something but I don't want to have the solder get onto adjacent areas, I coat the areas with Wite-Out by Bic. It is a typewriter correction fluid. It does a good job of keeping the silver solder away, but then after the soldering is finished, I have a Devil of a time getting the Wite-Out off. This week when I siver soldered the needle onto the knurled brass needle cap on the carburetor I was building, I coated the knurling with Wite Out. Then I tried afterwards to get the Wite out off. I tried paint thinner, Varsol, rubbing alcohol, dishsoap, Goo Gone, and a high strength degreaser. None of them dissolved it. I finally got it mostly off scrubbing with toothpaste, hot water, and an old toothbrush. You can't sand it off or get too aggressive, or it damages the brass knurling. Does anybody know of something that will dissolve this stuff?---Brian