Those plaster cranberries are on my tree, even as I write this.

IIRC, the stuff was simply very fine glass fiber. Your hands itched like the dickens after handling it (microscopic glass splinters), which may be the reason for its disappearance.

And we used to call that white fluffy stuff Angel Hair! Wonder if it turned out to be harmful you never see it for sale and I'm in NYC where you can buy just about ANYTHING!

I remember those red berries! They were made out of plaster. The stem was florist wire. The berries had obviously been painted by dipping.

I can't remember what the stems were like, perhaps they were of wire wrapped in green cotton thread in the style of early "Double Cotton Covered" small-gauge electrical wire.

The berries I saw were attached to a green-painted wooden skewer. My uncle, who mass-produced Christmas wreaths and grave blankets, used these as trimming.