There is a big risk the old wires are "welded" in at some points, which even if I could break, may leave sharp points which could damage new wire. Also, i'm not 100% sure these isn't some break in the line somewhere I haven't dug up yet, and its got an awkward angle at the end. So rather than investing in a puller, etc., and a days worth of effort pulling for something that may or may not be worth it (maybe 50/50 shot?). I'm gonna go with a sure thing and rent a trencher for a day and put in the new line. I'll feel a bit better about it knowing everything is complete and clean, even if it costs a couple extra bucks.Well since it is conduit the whole way then why not use the old wire to pull through the new wire and save a step? Ditto on the wire pulling lube. It is cheap and works incredibly well..