if you arrived here from a link on Pinterest or another tutorial/craft site, I have posted a "tutorial" on how I enamel the pennies.  It's here
Oh what fun I had in the workshop yesterday.  For the last six months, I have been collecting information and supplies to try torch fired enamel and finally gave it a try this weekend.  And I'm hooked.  I love it!!! Armed with a tutorial or two (and a comprehensive lesson on using the torch from my patient SO) I drilled some pennies; cleaned them thoroughly and then set out to color them like jelly beans!  As a surprise, my DSO bought me a "starter kit" (of sorts) of assorted enamel powders - 14 little bags of color - to play with as I wanted.  I couldn't wait to get started.
Using the first tutorial I found, I mixed my first enamel powder color choice with distilled water (50/50 ratio) and filled in the top of my first penny.......a penny I hadn't drilled.  The tutorial said to let the enamel and water mixture dry but I did not have the patience to let it dry, so I fired away.  I was a little tentative with the torch at first, but wisely started out making some copper head pins which relaxed my fears a little.  After the first penny was fired, I let it cool in a fiber blanket.  Once it cooled down, I was thrilled with the color and look of it and couldn't wait to do more.  
Head Pins
Faced with the 14 bags of assorted colors, I couldn't wait to try more colors.  Using a screen from a faucet (I absolutely have to get a small hand held sifter) I sifted the colors directly onto the cleaned pennies - and did layers of colors.  
Turquoise enamel powder
Base of opaque orange with a layer of red on top
A layer of golden brown with a layer of turquoise on top
Golden brown with a sifting of my run-off waste
Just to prove that I really used pennies!!
A couple of great, informative articles/tutorials on how to torch fire enamel:
