Mentholated spirits? Sounds like booze for a sore throat to a Yank like me! Is this the same stuff there here in the U.S. we'd call isopropyl alcohol (IPA)?
Anyway, IPA is what I use with great success. It's available on the "health and beauty" aisle, but don't use that stuff because it contains lots of water. Use the stuff from the paint aisle that's used as shellac thinner. It's cheaper in the long run and is pure IPA with no water. DO NOT USE any other solvents such as lacquer thinner, paint thinner, acetone or whatever because it'll eat the contact alive. I've used IPA to clean remotes and calculators -- anything using those conductive pads. Just take the remote apart and clean each button with a wet cotton swab and dry off each with a (what else?) dry swab. Run over the PCB contact grids as well.
Dean