I already used US and Canadian pennies (pre-1982 for the appropriate copper content) to make enamelled pendants and to join in colourful enamelled bracelets (see Steven James' tutorial at beaducation.com). Here is a penny that I punched in the centre and raku enamelled.
I went through my extensive coin collection to weed out the best pennies for the job. While I was doing that I remembered that when my son was little a friend of ours, who toured all over the world with the Barenaked Ladies, gave him a tin filled with pocket change per diem leftovers from his travels. I dug it out and the fun began.
First I tried to find matching pairs of coins. Once I did I used a screw down hole punch to create a hole in the coins. A handheld hole punch doesn't have the strength you need to punch a hole in a coin. I use a centre finder and a Sharpie to mark the centre of the coin.
Dap the coins. Remember, start in the largest depression with a matching dap then go smaller. You get a much better finished product if you are patient and work your piece down in depth slowly and consistently. You want the bead cap curved enough to tightly cradle the top of your bead. The hole will change in size and shape with dapping, so be prepared to file it out or even repunch the hole (carefully).
Find a bead with a large enough hole in it.
I use a file to enlarge the punched hole to make sure the copper tubing fits through.
This bead is capped with two copper coins. You can see where the copper tubing comes through. I will mark it with a Sharpie then cut the tubing and finish riveting to hold the pieces together. Cut your riveting tube slightly longer than your bead and cap stack. Flare one end of the tubing, assemble your bead with caps in place and flare the other end with your riveting hammer. You can also start with rivets that are pre-flared for you on one end. Just make sure they are long enough to go through both caps and your bead.
Repeat for a pair of earrings or finish with some beads and a wrapped loop to create a pendant. Join several together in different sizes and types of coins for a boho-look bracelet. If you also collect beads on your travels you can create the perfect souvenir bracelet to wear as a reminder of your trip.