OK - tried it out on an old junker. I bought the bluing cream rather than the liquid. And I got a bottle of blue and rust remover to apply beforehand. Slightly disconcerting health warning on the back of the remover: "Contains chemicals that are known to the State of California to cause cancer and birth defects...". The cream just gets applied with a clean cloth. Otherwise, everything's done the same as Josh mentioned.

I did the whole blade. If people are interested I'll post a pic later today. Had to be careful with the entire blade to avoid splotchy-ness (which I didn't avoid on the first coat ). Looks pretty good. One thing to note is that it ruined the edge (I guess because it's acid). Next time I might try taping along the edge...

Oh, and one other thing. I thought that a Wapi with nice blued scales would look great, so I tried the cream on the scales.... For some reason I thought the scales of the Wapi were just carbon steel, like the blade. Nope. Stainless I guess, because the bluing had absolutely no effect at all (although the heads of the pins are now a lovely metallic blue ) .

James.