JA wrote:
We're remodelling a basement and need to remove hard cut (masonry) nails
that are along side a window. There is no way to reach the nails with a
hammer, so pulling them out or pounding them flush is not an option.
[snip]
There's no way to get a grinder near them. I have about a 3/4" clearance.

If you have a Dremel-style tool, there is a flexible-neck attachment
for many of the models that would allow you to get into a tight space
with one of those universal mini-disks, you know: the ones that grind,
sand, cut through everything and make julienne fries. I've had great
success cutting through all manner of screws, nails and other fasteners
with a small rotary tool and those disks.

Of course, as others have warned, please, PLEASE wear eye protection as
those disks will throw off sparks and chips as they cut.