i found some compounding paste and used a fine steel wire brush, the brass got reasonably better

also i got an ultrasonic cleaner on amazon, gonna test it out soon on some intricate tuner unit parts
in the mean while, please enjoy the tuner coil before and after photos smile

the center double coil halves had broken free from each they should be glued together so they can't move
i ended up rewinding the coil after all the brittle gyptal flaked off and the windings came loose
-s
Attachments
switch_clean.jpg (163.07 KB, 175 downloads)
coils.jpg (104.04 KB, 177 downloads)
coils2.jpg (121.09 KB, 176 downloads)
coil_broke.jpg (66.23 KB, 180 downloads)
coil_fixed.jpg (80.41 KB, 178 downloads)