Is aluminium oxide recognised as a lung irritant? I've just taken the rim tape off a wheel that I've had for about four years. The tape, which was some sort of woven plastic, had been on there since the wheel was made, and I think the bike had been in the shop for about a year before I bought it, so at least five years. When I removed it, clouds of white powder came out and made me cough, quite a lot. I presume it was aluminium oxide, probably from galvanic corrosion between metals as it was all around the nipple holes. Anyway, I think I'll just cut the spokes off the other wheel rather than unthread them; they're only plain gauge anyway (the rims are worn out, the hubs are still in good condition).