Having been donated a homebrew "L" antenna tuner, with
an unidentified roller coaster (about 1 1/4" in diameter, with
a plastic facia turns counter marked "antenna loading" with the
plastic facia looking like a CRT's barrel distortion, any ideas
as to its origin, anyone?) but a fairly large domestic tuning
capacitor, I needed to remove the gunge that had accumulated
after some years in a garden shed.

Lo! And behold! An ideal tool is to be found in dental floss,
a bit difficult to thread it between to start with, (hook it with
a paper clip) but once going, it's in its element!