I had a job in a US Gov't metallurgical laboratory when I was in school. They had a bench-mounted belt sander - very old and beautiful cast iron machine. The sander was vented into a 4" galvanized smokepipe vacuum line that ran up the wall about 10 feet then overhead about 40 feet until you lost sight of it.One day I decided to put an edge on a knife using the belt sander. What I didn't know is that the guy who generally worked in that lab used the belt sander exclusively for magnesium.
All across the ceiling the bottom of the tin pipe glowed a brilliant orange - very impressive. Zinc dripped like condensation onto the floor. Ooops.