Tim Wescott wrote:
Place the jaws of the pliers so that they are just over, but not
engaging the nail head. Push _up_, _hard_. See if that gives you
clearance to grab the head.

No way. But, what DID work was to hold the pliers there and tap _up_
with a hammer. A mallet, actually, with a head big enough to hit both
handles at once.

The majority of nails can be pried from behind, but the rusty ones can't
and this should "work a treat" on them.

Thanks,
Bob