I recently purchased a "CircuitWriter" conductive pen from Radio Shak online. It was $9.95 and is used for darwing traces on PCB's. The application is a little too think to use directly on the L1 bridges, but using a needle or a toothpick works great. If you mess up, just rub it clean with some alochol or acetone. Dries is seconds, and provides an ideal connections. I am running my Duron750 at 1000Mhz, wheras before with a "pencil" unlock it would only do 960MHz.
-Aaron