I was up at a wood show in Ontario last fall and watched Rob Colson make hand made dovetails faster than most people can make them with a router.
I noticed that he had a chunk of parafin that he would squiggle across the bottom of his hand planes nearly every time he picked them up to use one.
I tried it on mine and it really improves the performance. I've mentioned it to a few people and they just look at me like I'm nuts (well, more so than usual).
Does anyone else do this?