Separating

I wanted to prime a bin of coarse material with worms, but didn’t want to spend hours teasing through material with a teaspoon.

I had a metal mesh-tray, previously used for filing papers on a desk.

I reasoned that if I dumped material on the tray, healthy worms would escape the light by traveling downwards, through the mesh, onto a collector.

Here is a half-gallon of material dumped onto a plastic cloth. Extracting worms from this could take me quite a wile, because the material is a mixture ranging from castings all the way to clumps of wet shredded paper.
This is the sheet of castings after the first batch of material. I gave the mesh tray a gentle shake to deposit a thin layer of castings, and the worms are still making themselves at home.
Here is my mesh tray. I have removed the material that sat there for an hour. I figure that the robust worms have migrated downwards, away from the light, through the mesh and into the thin sheet of castings underneath.

Here we see my mesh-tray sitting on top of the sheet of castings, with about a half-gallon of material dumped onto the tray.
Here is the sheet of castings after the fourth pile of material has been left out for an hour. The sheet is about ½ cm deep, and the worms have scurried out of sight.
We are left with the nucleus of writhing worms. These are visible because I turned the small cone with the teaspoon just before taking the photo.I saw plenty of eggs as I teased away the castings, so in the end I tossed the castings and the worms into the bin.