I was staring at my collection of empty cigar aluminum tubes, and wondered if I could do something with them. I graped my cutter start making tiny slits on one, and dumped some beads into it. I have two of these in my 40 count desktop, and they've been working wonderfully. They look much better the empty puck I kept the beads in before. Can anyone see a problem with turning tubos into humi devices? Do aluminum rust?