This is something I read in " Experimental Physics" or at least a
title very close to that. The author is "Strong " and it available as
a reprint from Linsey. I have tried it.

You need something kind of like a carbon arc torch but insulated for
high voltage and I just used copper wire. I think carbon would be bad.
Tig tungstens would likely be best.
Anyway it arcs just like a jacobs ladder.
You just move it over the glass so the plasma is up against the surface
of the glass. Anything adhering by electric charge blows away. Oils
oxidize, you probably die from ozone ( but only if the ozone from a
jacobs ladder kills you ).

Dan