WD-40 will work , but that stuff stinks !! and could also make the control worse after time becuase other dirty crap will have something to stick even better to )-: lighter fluid will work as well it just depends on what ? fluid will dry very fast with the odor disapating quickly unlike WD-40 and drys clean unlike WD-40. These are just cheap quick ways of getting the job done. 10.00 bucks a can for some good stuff is the way to go , especially if you plan on using it often ? if not and it's only for a Ebay special that your just trying to bring back to life , 1.29 cent can of Ronson Lighter Fluid will work in the controls just spray a stream in the control as carefully as you can to isolate it from other radio parts,shack out any excess and work the control back and forth for a minute or so , this would pretty much apply to anything you might use. The good stuff always seems to be under some pretty strong pressure out and if you can afford the extra cash I would certainly go that direction. Good luck to you.