Using the holy trinity of Deoxit products (Gold, Faderlube, and Deoxit Red, I was able to restore the function and feel of the switches on the Sustainor 100 and the sliding potentiometers on the GEQ.
Shiny contacts protected with Deoxit Gold. I was able to drop in some of the Deoxit Red and then swab off the corrosion from the sides of the switch chassis. I then blew out any residue, cleaned with denatured alcohol, and then swabbed on a little Deoxit Gold to protect the contacts from future abuse.
I removed each sliding potentiometer, one at a time, and disassembled each one to thoroughly inspect and clean the bearing surfaces.
Filthy fader before and after! I used the same process as above, but skipped the Deoxit Red and went in with the denatured alcohol to clean the board and chassis of each switch. After pic is before the Gold was applied. I could have cleaned these more deeply, but I've learned to leave well enough alone with vintage gear.
I had to hustle a spot repair for lack of time. The 2.8K slider was not functioning and I found out why. The wiper had dislodged from the slider carrier and was crushed into the inside corner of the slider chassis. The little legs were bent out of shape, so I used my handy forceps to carefully reform them. A little superglue gel and a soldering iron were used to weld the piece back onto the carrier. All set!
The end result is pretty amazing. The Sustainor's tones have immensely improved and the GEQ, while still not 100% functional, is usable again. The 3 bass band sliders don't seem to be functioning - only tested in headphones, so once I return from my trip home I'll touch up all the solder connections coming off of the ribbon cables.
Hope you all are well!