Have a pair in every brand.
1
First you need to get a hold of two botte caps, preferably the same kind. If they are a bit bashed up, bash them in to shape with a hammer. Make a small hole in the top, center of each cap with a stanley knife.
2
Slip jump rings through the holes on the caps.
3
Cut two short lengths of chain and slip the chains on to the jump rings.
4
Attach another jump ring on to the top of each chain and add an earring hook. Close the hoop and run off to the pub to show your friends.