Really not gonna touch this one...

That's what I'm thinking. Residue from some exotic cleaner that was used. The wrap may have absorbed some of it.

John

A lot of chrome cleaners are dyed blue for some reason. This could be chrome cleaner residue which crept under the lugs and badge from polishing over the years.

The Copper Sulphate theory does have some merit but it requires some sulphur to be in contact with the copper badge or copper underplate on the lugs.There would have to have been contact with a reasonable level of unbound sulphur. Another copper ion that could occur , would be copper acetate , which is also blue and has been used commercially as a dye. It is created by the reaction of acetic acid(vinegar) on copper. Perhaps a previous owner used vinegar to clean some parts?

yeah, probably not a good idea to be touching that....

I like the old cleaner/polish idea the best and how it's possibly on the wood inside and not on or near any metal parts. Clapping Happy2 Kleening

Guess you need to look at my user name....

Thanks for helping solve the mystery, guys. Some kind of solvent/cleaner seems to make sense. Luckily it's all covered with the lugs, etc. on the outside and I'm not too concerned about the interior, as it's completely dry.

I shot a pic of the inside of the shell to show you scientifically-inclined where it gathered. It's consistently around the holes but somehow crept all the way down to the rings. Somebody was pretty sloppy with the cleaner.

Thanks again for your help!

I found this:

http://www.daff.gov.au/aqis/quarantine/pests-diseases/blue-stain-fungi

John

Wow! We made need to create a new section for "Quarantined Drums". I like the idea of gamma irradiation treatment. Way to dig deep, John. Very interesting. Thanks.