The only issue with copper is corrosion around the knot, I would weather or polish it as you like and give it a couple of coats of brass lacquer, at least in the hole and lip around it for the knot to prevent this. Otherwise your likely to get green chunks in the bristles and the lather they make.
Originally Posted by badgerRN
Bearing the burden of responsibility..... It's probably my fault.
Treat your silver as if it were earthenware and your earthenware as if it were silver - Seneca, Letters of a Stoic