Replace audio knobs

I just wondered if someone has ever removed the audio knobs.
I wanted to eventually put in some others with more grip, perhaps with grooves or more sticky plastic.
On most devices the knobs have a screw on the top / on the side, OR simply are to be pulled out, but i don't trust to do it on the prius... hehe :-/
I saw some pictures of a disassembled central-part-of-the-prius in a past post, but cannot remember where...