On Thu, 8 Nov 2012 07:34:34 -0800, "Fred \"Fred\" Fred"
wrote:

Need sage advice on how to removing an old leaking hot water shut-off valve and salvage the nut.
Can't budge the nut and has bimetal corrosion. Would anything work better than std penetrating oil or WD40?

Use penetrating oil and vibration. Wet the nut and tap it with a
wrench so the fluid enters the threads. Allow it to set overnight,
wet it again. Why is saving the nut so important?

A nut splitter will break the nut so you can get it off.