Originally posted by pres589
The "something in a can" was probably contact cleaner. Can get it lots of places, like automotive parts stores, Radio Shack (is that still a thing?), etc. Might follow up with compressed air to further clean the dial's electrical parts out and better flush out any contaminants.
The K-3 is a sealed system and I doubt very much that you will be able to get enough contact cleaner into the area to get what ever contacts there are clean.
Can you feel the detents as you rotate the mode dial? If no detents are felt something has to have come loose so the best thing to do use the camera while on vacation and then send it in for repair. Spraying contact cleaner not knowing what sort of material the mode dial is made of can be risky, I've seen contact cleaner destroy plastic. Just my two cents.
Larry