[Arran]

Here is how I would do it, get an old toater oven or hotplate (the kind that has burners like an electric stove) from somewhere and a small metal tray, the toaster oven usually comes with one. Cover the metal tray with aluminum foil, place the block condenser can on the sheet and bake the can in the toaster oven, or on the hotplate, at about 200-250 until the tar and wax gets soft. On the hotplate you may be able to place it topside down but you will probably need to place the can on it's side to fit it in the toaster oven. Once it's soft you can start pulling out the contents either but the leads like some have or by screwing a large corkscrew or a large wood screw into one of the old condensers. I have tried melting these things out by placing them bottomside down and it just makes things more messy then the other two, toaster oven melts the contents quicker but the hotplate method is less messy and is the method shown in the Ghirardi Radio Servicing manual believe it or not.
Regards
Arran