I to have had success cleaning my AFM.  Let me add something to Marshall
Ruskin's notes.

You can easily remove the "sweep arm" to bend the contacts. The arm is held
onto the shaft by a screw clamp. There is another screw that will allow
adjustment of the arm on the shaft, don't loosen that one!
You don't have to bend the copper arms much.

The 4 prong connector can be removed form the AFM (4 screws on the outside)
and the contact points that connect to the circuit board can be cleaned.

The carbon track can be cleaned with 95% iso propanol or 95% ethanol. Both
work as well as any proprietary cleaners in this case. Use a cotton tip
applicator, and don't scrub a way too much of the carbon!

Metal to metal electrical contacts can be cleaned with a pencil eraser.

I used a product called "Jiff-Action" to protect the contacts after
cleaning. Its a cleaner/protectant for electronics, does a great job on
removing "noise" from carbon track type potentiometers(ie volume
adjustment).

Just recently, and just for laughs, I have been playing around with the AFM
spring tension. The tension can be adjusted very easily with only a phillips
screwdriver. The tip of the screwdriver engages the cogs on the adjusting
wheel and by rotating the driver, the adjusting wheel will turn. The
adjusting wheel is held by a spring wire that engages the cogs. The tension
on this wire such that it allows adjustment.

Alistair