DON'T USE ANYTHING STRONGER THAN DISH SOAP AND WATER ON THE BLACK LETTERING ON THE TRANSPARENT PART OF THE DIALS!! It's really delicate!

It'll clean the numbers right off! Ask me how I know......

For the actual plastics, case parts, knobs, and faceplate etc, I wash with standard dish soap and water with a small soft brush, then once it's dry, I'll go over with isopropyl alcohol to get anything the soap couldn't clean off.
Sometimes I'll stick non-painted/screen-printed plastics and faceplates in the dishwasher when the wife isn't looking.
