The best way to clean those rubber contacts is to take the entire keyboard apart and remove the rubber contact membranes. Then clean the membranes with a gentle rinse in warm water and a little detergent followed by a rinse with clean water and a final rinse with RO water. (you can get RO water from most aquarium suppliers). If there is dirt residue on the circuit board, losen the dirt with a damp cloth and finally give it a wipe with a clean damp cloth with more RO water. RO (reverse Osmosis) or deionised water will be free from dissolved salts and leave no residue. It is also safe on plastics unlike many solvent based products. I have used this method on a number of synths with good results. There are some good video guides on disassembling keybeds on You Tube.
Date published: 2016-07-30