HP-67 cleaning pcb keyboard contacts

[coitboy2000]

Hi All,

I am trying to revive an old HP-67 and, thanks to Tony (aka Teenix) have a new replacement pcb (and a working card reader thanks Tony!!) as the old one had died. The calculator has had a tough life and some corrosion exists on the keyboard/pcb/domes. The story began in this post:

https://www.hpmuseum.org/forum/thread-15727.html

Anyway, the calculator has come back to life but the results on the leds's is somewhat random when I press certain keys. The keyboard is the likely culprit (shorts etc) and even though I have scrubbed it with alcohol & a toothbrush and also ran some paper under each contact the problem still exists. Is there another way to clean the keyboard i.e. could I desolder it from the main board and immerse in vinegar or something else ? Just looking for some ideas.

Cheers

Richard