http://video.google.ca/videoplay?docid= ... 2&hl=en-CA
*CORECTION* In the video I first say to heat the pick up to a cherry red, but I meant to say orange.

You'll need
~Picks to temper
~Heat source capable of getting the metal red hot ( I used a propane torch, but you could use a bed of coals, bar-b-que, stove, etc.)
~Pliers or vice grips to hold the pick\
~Sandpaper or a dremel (I used 320, but anything that will get the bristle nice and shiny will work, this is important to see the fine colour changes when heating)
~A jar of water to quench the pick in.
~Fire extinguisher, and goggles and gloves if you feel so inclined.
Heres what you need to do
First, get your pick all cleaned up. You'll want to remove any glue, paint, or other gunk on it.
Next, fire up your heat source. Heat you pick up to a nice bright orange, then, while its still very hot, quench it.
At this point, the metal will be very hard, but also very brittle. So be careful when handling the picks, as they may break.
Now, sand the pick so that its a shiny silver. This is important because you will need to be able to see the colour changes in the metal.
Finally, heat the metal up ever so slightly so that it changes colour from a silver to a light blue. heat the metal up to this blue colour, then quench it. Make sure to heat all the metal that you got hot in the first step, and not to miss any bits because they will remain brittle and break easily.
Any you're done! The result should be nice and hard, but not brittle.
A couple of pointers
~This works nicely on cheap bi-metal hacksaw blades (the 8 pack for a buck). After tempering with this method, they're awesome picks, nice and hard and durable.
~Don't overheat the picks in the second step, when trying to turn them blue, or you'll have to start all over again.
Enjoy!