Step 2: Cut up Mo-bo.
You will need a dust mask when cutting up and filing the motherboard pieces, although it most likely won't kill you breathing in the PCB dust it will not do any good and could possibly destroy your lungs. I didn't wear a dust mask but my excuse is that there wasn't any available, it doesn't smell nice and can get quite nauseating.
The easiest way for cutting the mo-bo. is to cut strips of the width that you want for your bracelet, so cutting strips down the mo-bo. of your choicest electrical components, and then cut the strip up into segments. On after thoughts I would make the segments a little longer so you don't need as many for the circumference around the wrist.
Also salvage the bigger chips because they can become segments and will add geek points to it.
After you have cut the pieces washing them in water will remove most of the dust off them, don't worry, water won't affect them.