I have good luck with the tapered straight seat wrench. I just bash on
it, cutting into the brass, and then unscrew it. If that doesn't work, you
could trim a hacksaw blade to fit inside the seat, and then cut the seat in
half, down to the threads. It'll come out then.
Thanks for the replies. I asked at the local plumbing supply as well, and
was "loaned" ($1/day) the proper size "easy out " to fit just inside the
seat. Soaked the threads with WD40, applied a little torque via a 1/4"
drive rachet, and out came the seat!! I now have a like new hot water valve
with new seat and washer.