The simplest DIY possible.
Use 2 12" pieces of string or fishing line.
Loop 1 string under the knob so you you end up holding both ends in one hand. Then loop the second string under the knob so that you end up holding both of it's ends with the other hand. Pull up and off pops the knob.
I like this method on stubborn guitar knobs because I don't want to pry against the guitar's surface.
Freddy :sam:
Freedie this would be for removing certain knobs on a console. They are atteched via a special screw plug that a regular screw driver will not get out...
Are you asking about tamper proof screws or what ever they are called is it a roundhead with two holes at the edge? If so a good electronic place should have a kit with differnt type drivers to fit all kind of crazy screws.
For collet knobs;
http://www.canford.co.uk/commerce/resources/catdetails/2747.pdf
Part numbers 58-957 & 58-958 .... this what you mean?
Some of the AMEK consoles have a similar arrangement for the nuts which secure the pots to the front panels.
We have a custom made pair of hand tools for that size (which we stock).