[vintageradiojohn]

I use a dental pick to pry the vent cap off. Then use a dremmel burr to enlarge the hole. Needle-nose pliers used to twist & remove the guts in pieces. I solder a new electrolyic to a brass bolt, & drill a small hole in the side of the can near the bottom for the neg. lead.
The whole works fits into the hole in the top, & then put the vent cap back on.
It takes a bit of time, but the results are worth it.