[Ron Ramirez]

I cut mine open in a similar manner to the technique Ed mentioned, only I use a Dremel tool with a flat cut-off wheel instead of a hacksaw.

I replace the original aluminum positive electrode with a piece of 12 gauge copper wire, with black electrical tape wrapped around it; just enough so that it fits snugly in the hole where the old rubber used to be. Then seal that in place on the inside. I remove the solder terminal that is crimped on to the aluminum electrode on the outside of the can (this is difficult, but can be done with patience and a bit of luck) and attach it to the copper wire on the outside (EDIT: I not only re-crimp it to the copper, but also solder it to ensure a solid electrical connection). I solder the positive terminal of the new electrolytic on the inside end of the copper wire. The negative lead is extended if necessary with a bit of wire, and run through the bottom of the can by drilling a hole in it.

I've been meaning to take pictures of my technique, but my digital camera does not do so well on close-ups.