Honestly, I can't say for sure which way to go mate, especially as I don't know if spraying them would void any warranty or whatever.
If you don't already have it, I strongly recommend you buy a can of Caig DeOxit™. It's been the undisputed king of electrical-contact cleaners since God knows when with audio engineers the world over. One can should last you a lifetime. As a bonus, you'll find yourself fixing all manner of obscure problems you'd otherwise have written off as throwaway items.
Seriously man, the stuff's magic. Use it on mixing-desk faders and pots, input jacks, outboard gear... anything where electrical contacts are critical. Leaves no residue and is safe for plastics.
So, that'd be my next move with the POD. Spray, turn the knob / switch the switch, wait a few minutes and spray again to remove the loosened residue.