Electro 5 HP - Dead key

[johnny royale]

I am trying to fix a dead key in my Electro 5 HP. Upon opening the board and inspecting the sensors I'm realizing they are all pretty dirty...

My question - is it worth it to try and clean the sensors? Or should I just replace them all? i.e. Are they really just dirty or is this a sign that they are just going to continue to need to be fixed more and more frequently until they ultimately die? I have cleaned the dead key sensor twice now with a pencil eraser after watching a youtube video and that fixed the problem for a while but eventually it came back worse than before so i am trying to not cause more damage or waste time if a more long-term fix is unavoidable at this point. If cleaning them all is worth the work, what should I use? On youtube I have seen people rubbing both contacts with cue-tips and either distilled water and rubbing alcohol.

Also, if after cleaning or replacing the sensors attached to the removable boots, I realize the problem is in the sensors on the actual circuit board, what is the best way to clean/fix those? I watched some videos of people using conductive paint on the board but want to double check that as well.

Thank you!