Finally got a chance to put the dash back together a few days ago. It's taken a while because I'm thinking I should do it right while I have it all apart. I don't want to take the instrument panel out again any time soon.
Which sort of reminds me of an old Peter Egan column in Road & Track magazine many years ago in which he talked about an MGB on which he "went to replace the brake master cylinder and wound up restoring the whole car."
Enter a brand-new dash trim piece! Why try to clean up the old one when you can just put a new one on?
I recognized Rüsselsheim, Germany immediately as the location of the Opel car company (owned by GM since 1931!).
This is one of the power mirror switches - made in Holland by iku...now Mirror Controls International.
It just pries out of the panel.
I got one screwdriver under one side, and a second one on the other side. Couldn't get a picture because it popped off after some concerted levering.
It looks like I damaged it - but it's fine. Just one tiny nick.
The solution was to use a heavier control - a wirewound rheostat. You can see the winding and the contact in this picture.
It's held on with an adhesive on the back of the cover.
I soaked them in a weak mixture of Simple Green and water for about 30 minutes, rinsed them under warm water, and repeated. They're nice and clean now.
It was a lot easier cleaning all the parts while the dash panel was off. There are always some corners you can't reach while it's mounted on the car.
I also cleaned all of the switch contacts with contact cleaner.
I can see where the electric mirrors were optional on some cars, so those holes would be covered by the panel. But you'd think every car would have the dimmer.
Then I carefully cut the panel with an X-acto knife. This picture is misleading - I didn't do it freehand. I used a metal ruler as a guide. I did not want to ruin my nice new cover.
I suspect the factory had punches to do these cutouts more cleanly than cutting them with a knife.
You can also see the paper covering the 3M VHB adhesive on the back of the panel.
Then I pressed it down everywhere. The adhesive is pretty tacky, but you can remove it and relocate the cover if needed.
This is as close to new as you're going to get.
Oh, I didn't bother putting the ugly UNLEADED FUEL ONLY badge back on! I just have a nice clean expanse of panel next to the radio opening now. Looks a lot better I think.
Next: back in the car and does our clock work?