E3D has been using a wire brush on their tool changer test fixture. With hardened steel nozzles (or some other abrasive resistant material) we wouldn't have to worry so much about wire brushes damaging the nozzle.
I'm not sure a non-stick (Teflon) brush would actually clean anything off the nozzle, but I could be wrong.
We are not looking at capacitive leveling presently, but we will likely want to find a way to do automatic nozzle offset calibration. Capacitive or not, this will likely require a pretty clean nozzle
I am looking at higher temperature plastic bristle brushes, since we will now be using higher temperatures and higher temp materials with this machine.
I found a brush that would fit that has PEEK bristles - https://www.gordonbrush.com/products/peek-specialty-end-brush-eb14p
They are kind of expensive at $31.16 each @qty 1000, but materials in our temperature range will be expensive. They also do custom brushes, so we might be able to work out something else with them.
the thing is if we have PEEK on the nozzle it would need to melt the PEEK to clean it, which would melt the bristles.
I have been having really good success with using a wiper pad i made that is made from high temp plumbers felt that has been treated with ABS in the same manner as the current wiper pads we use