I had the same problem years ago but never got the penny out, so i have a very expensive C/S coin now. The problem is that english pennies are a little bit larger then halfs and they vary slightly in diameter, so some pennies might fit and others of the same year will jam. Just sand the edge of a penny until it fits in the shell you use. I use a magnetic S&S with a penny that fits in the shell-part, took me about an hour with some sandpaper. It is copper so it is very easy to do. Just check your shell, it might be too wide now for a half. That can be fixed by inserting a half in the shell and rolling it over a hard surface while pressing down. A dent in the rim can be removed by laying it face-down on a close-up mat and using a round piece of wood or plastic to push the dent out. I use a round bic-lighter as 'anvil' on the inside and a small glass ashtray as 'hammer' by tapping it gently against the outside of the rim, if you get what i mean.