When I had one, I used a push-pin to make a hole in it. I slowly pushed and turned at the same time to "drill" the hole. I went a little on one side, then again on the opposite. Once finished, I put a VERY small dab of super glue to help reinforce the back side of where I made the hole. I used string however not a chain. I think it's too small to be able to loop a chain through.