Copper? Dragon

Hey all, I come to you again to show you my stuff. I don't usually look for metal, but I really loved this piece. I picked it up while in Andong-si South Korea. It's got some kinda weird oxidation in my opinion and some bizarre... chalky white stuff that I *really* want to remove but figured I should check with yall first. No discernable maker's mark that I've noticed and it looks to have lost its right horn at some point somehow. When picked up and tilted, it sounds like sand is inside of it. The mouth appears to have had something in/attached to it at some point? Maybe the molding process was just a bit tricky in some places? And is it okay to dust off the weird chalky white stuff?

 

It is cast brass. Asian brass usually has slightly different metal percentages, and can have other metals mixed in as well, but it is a brass-like alloy.
Brass always contains copper, so you were on the right track.

Maybe the sand grain sound is caused by particles of the clay core.

 

I'd brush it over with a soft brush, then wipe with a damp microfibre cloth.