Originally Posted by Beertintedgoggles
I can't remember where I first heard it (might have been here), but I've been using sewing machine oil in my fans since it's made for higher RPM components. All you do is peel back the sticker on the hub of the fan and place a drop or two into the center. Some fans may have a rubber plug in the middle instead of or in conjunction with the sticker that needs to be taken out. I do this on every fan in my PC (except PSU) and they all run like new. I've even done this to fans that have become noisy and vibrate and this calms them down drastically.
I've been doing it since I gave a crap about fans in my case. I use an industrial high-rpm oil though. It's good to do it as maintenence anyway,(every 4-6 months or so) less wear = less failure.