[TowerTalk] Corroded copper conductivity?

[Dan Zimmerman N3OX]

Has anyone measured corroded copper inductor Q vs. shiny new copper at
HF frequencies?

Specifically, I wonder if  there'd be any practical benefit to
polishing and coating a 3/4" copper pipe transmitting magnetic loop
with coil varnish?

The capacitor is a Jennings vacuum variable and the silver-plated cap
clamps have been soldered to the loop using solid silver plated copper
strap, so I don't have a particularly lossy capacitor arrangement.

I also know that shiny new copper vs. shiny new silver wouldn't make
much difference.  What I don't know is the conductivity penalty of
corroded copper.

The loop is just a fun experiment since I had the capacitor burning a
hole in my junkbox but I'm interested in seeing how well I can get it
to work vs. my larger antennas.

73,
Dan