On Saturday, May 29, 2021 at 2:55:31 PM UTC-7, micky wrote:

The remote works fine except for the buttons used the most, volume up
and down, channel up and down, power, and muting.

I took it apart and expected to find oxidized contact points, but no.
Instead those buttons, on the circuit board and on the buttons, are
shiny and a little bit sticky. ...

What is this, how does it get in there, and [what do I do about it}?

I have DeoxitIT, what I've read is the best, but I guess I've never used
it before, and it didn't remove the stickiness. Not only that, these
contacts aren't copper-colored, and as the name impplied, it's really to
remove and prevent oxidization, so I switched to isopropyl alcohol and
that did a good job.

The liquid (I think) is a plastic component intended to keep it flexible; a
'plasticizer'. Lots of plastic formulations 'sweat' this stuff, and isopropyl
is a good solvent for it. Glycerine, too, should work.

DeOxit formulations DO enhance contact, it's worth applying after cleaning.