Plastic cards are passé. The truly hip Muni rider tags onto the bus not with a Clipper card, but with a piece of handmade jewelry.
Initial attempts to hack the Clipper card by cutting out the chip were unsuccessful. It's just a microchip, after all; in order to talk to another device, it needs an intact antenna.
But British transit geeks have found a way to make it work. By dissolving the card's adhesive in acetone for a few hours, you can peel apart the layers, extracting the chip and a coiled metal look that acts as a transmitter. You just need to very, very delicately remove the components inside the card -- don't bend or tear anything, or it'll stop working.
Once you have the chip and the loop extracted, you can simply sew them into a wristband, weave them into a bracelet or even coil them into a ring. Of course, you do all this at your own risk, as any kind of tampering may render the equipment useless. And if it doesn't work at a fare gate, you'll have a tricky time explaining to a Muni employee, "No, really, I just dissolved it in acetone."
Replacing non-functioning Clipper cards is a difficult process. They can't just transfer your info from one card to another -- it can take several days, during which time you won't have access to the balance or passes on your card. Since Clipper card usage has increased significantly, it's likely that they'll need to figure out a way to deal with this problem sooner rather than later.
Of course, if your card doesn't let you through the subway gates, it's no big deal. You can always just wave your hands and waltz on through without paying.