The box that holds the main cutout (60A) is very sticky with that brown gunge that seems to appear in warm weather. My spark said (a few years ago) that it's nothing to worry about as it's put inside the service head/fuse for safety reasons and occasionally leaks slightly. Problem is that it's got onto the wife's nice new white trousers and I'm in the doghouse. Any suggestions for a safe way to give it a clean? I've wiped it with a dry kitchen towel, but that just spread it more.