It's not so much the insulating particles I'm concerned about; it's the
fact that the metal layer is really thin. I'd be concerned about
destroying it completely. Really fine emery paper would probably be
okay, but personally I wouldn't want to use coarser than 800 grit.


The zig-zag pattern of tracks they normally put on the printed circuit board
is solid enough to take a gentle clean with an ink rubber. Preferably those
old grey and white style ink and pencil rubbers (or eraser depending on
which school you went to!).

The fine abrasive cleans off the copper track nicely and is gentle enough to
use many times on the remote over the years.

The rubber pad that forms the buttons is easily cleaned with dish washing
detergent and your fingers in the kitchen sink. Allow it to dry before
putting it back together. If the little conductive bit has fallen off, then
you can cut one from another old dead remote control and glue it in place
with superglue (CA).

Hope this helps,
Peter