[sdiy] cleaning squishy rubber buttons

[Robin Whittle]

I once used alcohol (ethyl as "methylated spirits" or isopropyl alcohol,
I don't remember which) to clean the conductive rubber discs.  This
caused them to become less conductive or non-conductive.  While I think
this is probably not the usual behavior, I never did this again.

For the rubber contacts, I use a fresh piece of wet-and-dry black
silicon carbide abrasive paper.  240 grit is probably a good choice.  I
lightly abrade away the polished surface to create a fresh conductive
rubber surface.

For black-coated PCB inter-digitated contact fingers, I have just used
isopropyl alcohol.  Likewise for gold plated contact fingers, but I have
occasionally been tempted to very lightly roughen them with some
abrasive paper, probably with a finer grit, say 400, than what I used
for the rubber contacts.

  - Robin          http://www.firstpr.com.au/rwi/dfish/