Buffing compound comes in all sorts of types, mostly denoted by color. The chromium oxide which is usually green is the best, since it's incredibly fine (0.5 micron) but super abrasive. So it gives about the best polish obtainable in the fastest time. All the other stuff is either coarser, less abrasive, or wears down faster.
When I first found out about it from woodworking forums, I went down to the hardware store and got a fossilized set of buffing sticks. Other than the fact that that the wax base had hardened it worked OK. Later I got a better block from Lee Valley Tools in Canada. Despite giving a bunch away, I still have enough for my lifetime.
There is better stuff, scientific grade diamond lapping compound, which goes even finer. But that's expensive, and probably beyond our needs. Better to stay with something that can be crayoned onto a piece of cardboard or paper, then when the cardboard turns black with removed metal - it's thrown away (without crying over the cost).
You can read the sharpening paper with electron microscope pics, mentioned in the shaving thread, for details on how well it works.
Valve grinding compound is just carburundum - the stuff on emery sheets. I find that by rubbing it into well oiled leather that I can get very fast and good removal of wire edges and some sharpening. A person can also remove wire edges by slicing some newpapers, but that causes edge degradation. Even better than carburundum is the brown slurry from waterstones rubbed into oiled leather.
Given the low cost and little effort with cheap sharpening methods, it's all worth a try. A couple of years ago we did some edge holding tests over at outdoors magazine. I was amazed at how well a properly sharpened Mora did.
