How to Unstick a Sticky Shutter/Zoom button... Help?

[DMCFZRichie]

I used to have a Panasonic Lumix DMC-FZ4 until that recently broke.

Today I bought a used Panasonic Lumix DMC-FZ7 from Craigs list. I did check the camera out before handing over the money, but I didn't notice the problem until I got the camera back home.

The zoom/shutter ring sort of sticks. I hope it's not some fatal flaw that will ruin a purchase that I was otherwise excited about.. but perhaps you guys can help me figure out what methods or steps to employ in order to remedy this problem.

When I turn the zoom ring left or right it is more difficult to turn than it should be, and then sort of sticks in place and slowly slides back to center. The shutter button in the center of the ring is equally hard to press at times, though not all the time. Everything still WORKS, but just not as it SHOULD.

I thought about trying a can of compressed air into the nooks and crannies of the ring. I also thought about trying some lubricating oil like WD-40 or 3-in-1 oil, but I wasn't sure if those oils might damage the camera. Help!