I used a product similar to that which sordna posted on the stems of two keyboards... not that there was any particular reason to do so, but I had buckets of stems already out (I was doing a swap of clear stems from a POS board that I had set up as ergo clears into a Filco, and reinstalling the original brown stems in the POS board) and figured it couldn't hurt.
I can't say whether it is due to the lube or the fact that I was using used stems, but the Filco definitely feels smoother than my Leopold with clears. The POS board feels nice too although I have been using my Noppoo (also with browns) at home, and the more I use the latter, the smoother it feels, so there might be something of a breaking-in process going on here too.