[Arran]

 Those look similar to the RCA style paper caps of the late 1930s and early 40s, if they are then you can press the innards out using a mechanics socket on a table. You place the socket on the table, place one end of the the capacitor over the socket, then grab the body of the cap and push down, sometimes you will have to heat up the capacitor a bit first to soften the wax. This also works with those axial lead electrolytics with a cardboard sleeve over a metal can to get the sleeve off.  To reassemble you go in reverse order, capacitor, end disc, then roll the end back over.
Regards
Arran