BBadger

Well in that case i would recommend a tinker, once you have a go youll be thinking "well that was easy"

get the can off.
get a small drill bit and drill the head of the rivits off.
then knock them through so nothings holding the end cap/caps on.
Inner tube and packing will just slide right out and your left with just the sleeve which you can cut down or knock the dent out of. ( might need some new packing to depending on how dead the stuff in there is )

putting back together is just the reverse although can be abit tricky and require abit of leverage to get the end caps in place.
all in all it is an light afternoons work that really wont take long so all i can do is say have a go.

im sure there must be some one local to help aswell if you want a more experienced pair of hands to run through it.