What devices have you found useful when inspecting your stylii for cleanliness?

Oops 

and a flash light

My ears....

My electronic microscope.enjoy the music it's an art to set the turntable up

I have a Panasonic FF-394E X30 lighted scope I purchased years ago on a whim.  Like a little pocket, lighted microscope.  Kind of a cool little gadget for cartridge needle inspection.  There are usually a couple on Ebay.  

RB wrote, "my current tone arm is a fixed head-shell design so I cannot easily get a good viewing angle - the arm does not tilt much."  Do you really think one can inspect the rear of the stylus and the cantilever (which also can accumulate dirt and debris) without removing the cartridge from the headshell, in that situation?  All the magnification in the world is not going to allow a good view of the back end of the stylus and cantilever.  With my Triplanar, I can flip the headshell over on its back for inspection of the stylus/cantilever, without removing the cartridge from the tonearm or altering the azimuth (once the cartridge is reverted to playing position), but this does not seem to be possible with RB's tonearm.