Metal Bee Frames?

Dan told me he had a couple boxes of metal bee frames and if I wanted them, I could have them for free, next time he was driving by. Curious about who manufactured metal frames, I couldn't wait and drove over to pick them up-6 miles. They turned out to be queen excluders, 23 total. The wood framed excluders were used, the metal framed excluders look unused but showing rust. I'll put them in the lumber kiln and cook them at 250 degrees to kill AFB spores and melt the burr comb.