HP30b - reluctant key

[Chasfield]

No recommendation led me to WD40. I know, however, that the carrier solvent in it is potent stuff and thought it would be a good bet for breaking down whatever it was that was preventing good switch dome contact. In my judgment, the very slight residue of lubricant would probably be helpful insurance against future oxidation and would not hinder electrical contact. Time will tell.

The product is not suitable as an electrical contact maintenance spray - it is flammable for one thing and can break down some plastics, so I wouldn't go squirting it into electrical devices.

I have also found WD40 to be a good softening treatment for battery compartment verdigris, prior to polishing the contacts with a mini rotary brush. Once again, application should be minimal via a Q-tip. never spray it around.