I hesitate to post this in such a pedantic fashion in such erudite company but feel I must ....
Glazing sprigs should not be removed when the pane is set on a thin bedding of soft putty.
Consult the link I posted earlier - examine the pointed end of the illustrated sprigs. It is not some accident of manufacture that they are that peculiar shape. Just as a farrier's hoof nail has a bias cut point to guide it, so the tapered shape and pip steer the sprig gently against the glass.
It is inserted with the flattest straight edge to the glass, and generally set (for convenience) using the side of a 1" firmer chisel.
If you have one, a case-makers sprig set (hammer) shown below does a better/similar job.
Those of you that aren't already bored to a state of catalepsy will notice that the handle is offset to allow the long face to be slid flush/flat against the glass.
Feel free to call me a pedantic old scrote, although I prefer 'curmudgeon'......
Excuse me if I have repeated any previous post contents.
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