I had the same problem. What happened is i left mine in my car while i was working. This was not the first time either and when i got out of work in the late afternoon i noticed my sansa's wheel was incredibly hard to turn. I went home and searched for solutions and found your very same problem. I went downstairs and found that my dad had a pressurized can of Super Lubricant. 1 small, quick shot directly onto the wheel top and button got the spray lubricant on there good and i just wiped the excess lubricant into the wheel seams. Immediately start turning the wheel in either direction (try to switch back and forth) and it'll start to spin freely. The Heat of an enclosure like your purse or my car in the sun dries out lubricants just like the lube sansa applies in their factories to these products so just try this and tell me how it worked for ya if you still have it.
) ( :
P.S. stop applying alcohol. That's more of a cleaner and all it will do is temporarily fix the glide sticking problem while simutaneously drying it out. Bad method...go with your every-day spray-lube.