Hmm.
First thing is to remove the outer shell from the electronic innards.
You could use a pretty rough grade of sandpaper or emery cloth (roughly grade... 400?), stick it to a wooden block and sand away at the finish until it is all gone.
Repeat the process with a finer sandpaper and maybe wet-sand the shell. After that you could use a white matte spray to apply and undercoat.
Be patient with the paint, apply only THIN COATS. Once you've applied one coat, wait for it to dry (45-60min), sand it down slightly and repeat the spray-dry-and-sand process 2-3 times.
After your product is completely white, you can throw on any colour spray paint your want. Just bear in mind that metallic spray finishes take a longer time to dry.
And once you're done with the colour coat, you could finish it off with a lacquer coat, let it dry again, wet-sand it down and use autosol to polish it to a shine.
So while you're waiting for the stuff to dry, play guitar or do whatever lah.
Hope this helps