[villagetinker]

Interesting question. I did this up north, but have not looked at the fans down here. When I did this:
1. Turn off power, did I mention, turn off power!!
2. Remove blades as they typically need to come off to open case.
3. Tricky part, if you are really lucky, the case will open with 2 -3 bolts/screws removed. Then using an oiler with a long applicator apply to the bearings top and bottom. I used a good quality motor oil (30w).
4. Reassemble and test.

Since this is all done with the fan in place, you need to be very comfortable work from a ladder. The other way is to remove the fan from the ceiling, which is typically a 2 person job due to the weight of the fan, and do the lubrication on the workbench.

If you were really lucky, you might get away with WD-40 and a very careful spray job.

Just my thoughts, hope this helps.

OH did I mention, first thing, turn off the power??