A new one is $50 bucks from the zone. I would just replace it if its worn enough to rotate when using the blinker. You are missing out on some good speed settings otherwise!
Wish I could help you on the possibility of repairing it, but most switches I've ever seen seem easier to replace as opposed to trying to tinker with it. Even so, I'd bet you have to take it out even if something like contact cleaner would work. Why install it twice (if repair didn't fully work)
Best wishes for The White Mule