On Jan 27, 12:21 pm, wrote:
Anyone have advice on how best to remove old shut-off valves under a
bathroom sink? I've tried the WD-40 thing -- and it worked for all the
fittings -- except for where the valves themselves connect to the pipe
stems coming out of the walls.

Will heating them help?

Might -- particularly if they happen to be sweated fittings...

If not soldered, some heat can still be useful to loosen stuff -- just
be careful (obviously) w/ the open flame in a closed area. A piece of
sheet metal can be useful as a heat shield in that regard.