In Electrolytic Capacitor Removal NO Desoldering Required Paul Carlson says he uses lacquer thinner to clean circuit boards. On the Wikipedia article for Lacquer thinner it says these are usually mostly acetone. Personally I would only crack out the acetone if the IPA wasn’t working for me. Acetone is serious business.
So I asked about cleaning cables over here and apparently the material on the outside of a typical cable is PVC (Polyvinyl chloride), AKA “vinyl”. The jury is still out on what the best cleaner is for vinyl, but options include WD40, IPA, and metho (ethanol). I was worried that such solvents might damage PVC around electrical cables, but apparently it won’t.