I stumbled across this article on the WWW.

http://www.observationsblog.com/4/po...tery-acid.html

I have had a few occassions where I would have liked an aluminium winding check in a different colour from the standard colours available, either to match a reel or thread.

The attached method seems relatively easy and if done on a silver winding check could potentially produce any colour that you wanted.

I haven't tried this method and have put it up for interest sakes.

regards Adam