Sticky Boom Knobs and rubber material

[thiemo]

As far as I have heard one can also get the sticky material off with a solvent like alcohol or something similar. Then the knobs don't have the softer rubber surface anymore, but are very ok to use.

I can confirm this. Cleaned them with Bacillol-Wipes (basically alcohol wipes). You have to scrub a bit but then the rubber comes of and a pristine plastic finish is achieved.

[Transistor]

I fixed it with Isopropyl alcohol.
It takes a lot of patience but the results are very good

Video of the operation:
https://www.youtube.com/watch?v=oxEGiW0WtPo