The biggest prob with these rubber keypads seems to be dirty/oily
contacts. I see this much more often than actual worn out contact
surfaces. Has anyone figured out exactly what this oily substance is that
leaches out of the rubber onto the carbon pad and traces? I wonder if it
could be residual mold release being squeezed out of the rubber when
pressure is applied. Or perhaps finger oils somehow filtered thru the
soft rubber. Whatever it is, it takes time and apparently usage to
appear. Open up a new remote that's been on the department store shelf
for 2 years and u won't find this. Open up a 2-year old (or younger)
remote that's been used everyday and u likely will see it.

Could be oils soaking through the rubber. Most of my remotes have had things
spilled inside, and when I attempt to clean them the ultra-thin coating
comes off with the grime. And the worn-out buttons are usually the most-used
ones: power, vol +/-, and channel +/-.
It's amazing how dirty remote controls can get. You'd think people never
washed their hands at all.