I recently received the question set out below regarding the common manufacturing fault found on the underside of the flower holes on english flower frogs or blocks, in this case a Sowerby frog. Does anyone know the answer to the question, my guess is that it has something to do with the removal of the glass from the mould, but I am not sure:
"Got a question for you:
underneath the frogs, on some of the holes, are odd-looking flakes, as if
someone shaved glass away. The same effect as when a glass marble breaks.
Can't be damage; because of the way frog is made, couldn't be impact chips
in the hollow.
Do you have any idea what they are or why they're