Using modern electrolytic capacitor's can as a conductor?
This would be a bad thing to do. Most likely you won't get the rated capacitance, and the ESR will be worse. Also, even if it seems to work when its new, as noted in the comment, the aluminium can will easily oxidise, and your connection won't be reliable.

If you need an axial capacitor (contact at each end), that is what you ought to use. Modern components are more optimised than old ones, and are not as easy to abuse.