Unless you're extremely concerned about preserving original appearance, it's not necessary to unsolder the lugs and pull the can off intact.
If you cut it off and pull out the innards, it can be glued back on with JB Weld or a similar epoxy. Some people even use aluminum tape. It depends on how fussy you are about the appearance.
The following article has a section called
Replacing Electrolytic Capacitors. It includes links to other articles that show a variety of restuffing methods, with photos and descriptions:
http://antiqueradio.org/recap.htm
Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html