There are anti-static brushes still being used in the photography biz.
These come in a variety of sizes, and contain a polonium cartridge that's a
mild (so I am told!) radioactive emitter. I also remember reading in an R/C
Modelling magazine (in 1974?) about someone who built a diffrential
electrostatic field sensor with electrodes mounted on each wingtip. The
sensors picked up the gradient of the earth's electrostatic field. If
memory serves, the device was switched in when the plane went into an
uncontrolled spin, and would correct it to level flight. Interestingly
enough, I never heard of this again!

In theses days of femtoamp bias input opamps, rigging one of these should
be a lot easier.