i took mine to Ray's Camera, located in the Denver Pro Photo shop.
He revived my nearly dead Nikkor 35mm F/2 AI. The barrel was loose, the focus action was inconsistent and squeeky, and the focusing ring rubber grip had disintegrated. He tightened and lubricated everything, and found a rubber ring for my lens. Other than the worn off paint, the lens performed as if new! He had told me on several occassions that I should just junk it, rather than shell out the money to fix it...but then I showed him the prices of a decent 35mm f2 AI. I loved that lens AFTER he repaired it.
I like Ray for all of my Nikon stuff. (which I no longer own...now that I have a Contax G2)