I have a GE Capacitor that was never installed, but sloppily packed and has quite a few dents in it.  Would anybody use this, or throw it in yesterday's trash?  What would happen if I were to use this?  It looks different than the capacitor that came in my new GE M250R2, which, btw, works great, so I have no intent or incentive to replace it.  Just wondering what would happen if I were to use a dented capacitor if I were to build a 250 watt conversion?

I would not use it, as the dents may have broken the layers between the roll of foil, shorting or damaging it.

Depends how deep dents are vs how much reliability you want from the system. The demand for reliability from a personal collection lantern is not very high, since for you the cost of replacing a failed capacitor is only the cost of capacitor itself, and no production/etc is stopped by the failure

Picture ?

If I was you I would try the cap with a multimeter it should show a gradually increasing DC resistance if it does its probably OK. Next step try it on mains just to make sure there's no shorts

Depends how deep dents are vs how much reliability you want from the system. The demand for reliability from a personal collection lantern is not very high, since for you the cost of replacing a failed capacitor is only the cost of capacitor itself, and no production/etc is stopped by the failure

Picture ?

I will try to take a pic tomorrow and send it.  I tucked it away, and have to get it back out.  Also, it is worth mentioning that it is a 3rd party GE capacitor (not made for use on the assembly line, but made for the spare parts division)

As long as it is the correct spec it does not make difference.... Things get bad when inappropriate capacitor type is used such as X2 in series with lamp....