{Multiple replies packaged together to minimize list traffic...} I don't see any sign of a cotton packing around it (but maybe it's just sealed away where I can't see it). There is a gasket/washer of some sort of packing material / felting at one end, but I suspect that's for dust interception, not as an oil resevoir, as in the fan's normal operating orientation, it's on the bottom. Speaking of orientation, though: these fans, like most PDP-11 fans, send air downwards. I was thinking of flipping them, to send the heat upwards (its 'natural' direction), but after pondering a bit, I'm not sure this is a good idea: the air-flow on the intake side is diffuse, whereas on the output, it's a concentrated, directed blast - better for cooling boards, etc. Thanks very much for taking the time to do that; my only concern is to wonder if their experience is applicable, since these things are turning an order of magnitude faster than old household fans. That's what I've been working with so far, but I was wondering if it would last without going gummy. If they're happy with it for the long term, that sounds like it would be good for this too. Thanks for the tip; I'll see if I can find any here. Oddly enough, I had found something called Hoppe's Lubricating Oil on my shelf - it's for firearms and fishing reels, and explicitly claims that it "will not gum [or] harden", which also sounds like it might similar to the above, and just what's called for. I had seen reference online to people using synthetic automatic transmission fluid, but the stuff I looked at claimed to "stop leaks", which makes it sounds like it contains some agent which hardens (or at least coagulates) when exposed to air (although I would assume there was some exposure to air in the transmission?), which is definitely not what is wanted! Noel