Staining on the encoders

I have some yellow staining on the encoders of my recent purchases. Both the A4 and the AR are from the same seller and I don’t know if the guy was jamming with his curry dinner or what but its pissing me off.

How do you clean the encoders to get stains out without damaging them. Should I use a wet cloth here?

4 posts were merged into an existing topic: Replacement Elektron encoder knobs