What is the best filling for a pin cushion?

Polystyrene half ball - craft shop

Many were filled with sawdust, but you can use batting, foam, snippets of cloth and so on. None of those items, including the sawdust, would harm your needles or pins; usually, any sewing room has a few odd bits of batting or cloth scraps that can be stuffed into a pincushion.

most pin cousins com with a "tomato" and a "strawberry" the tomato is soft, the strawberry has sharp sand in it to sharpen the ends of the pin. for ease of use while quilting i put a 1/.4 inch thick left over piece of foam and glued it to a board scrap. wont roll away from you.

stainless steel cleaning pads

Fill with aluminium foil. This will ensure that your pins and needles stay sharp

Forty years ago I read directions on how to make darling pin cushions out of half a walnut shell, and it said to use fine sand as the filling.