I have not found a way to prevent worms from multiplying like crazy.

Oh, that's not what you meant.

I don't try to screen casting without allowing them to dry for several days first. The solution to your problem would depend on whether you are screening castings after the worms have been removed, or as a way to remove the worms. It would also depend on how much volume you are talking about.

I was attempting to screen the worms out of the castings.
I did that in the summer and it work well. Right now I am working with a 25 gallon full bin.

How about screening the cocoons out? What method did you use in the summer?

There are many different harvesting methods producing varying consistencies of screened castings. Some people want "pure" castings while others are content with rough/chunky vermicompost. The former obviously requires more effort.

I don't know what your goal is or what your time frame is. If I personally had 25 gal. of material that was 40-50% castings with only small pieces of bedding & food stock remaining, I would use one of the onion bag methods over a period of 1 month to remove most of the worms and allow some of the cocoons to hatch. At that point I would use the vermicompost as-is.

Coarse VC still has plenty of food material, so I would use it in my garden or containers. Any worms remaining or babies that eventually hatch would continue to process the VC in the field. I'd probably add a bit of leaf mulch or something else that would continue to feed them. The little worm colonies would continue to produce castings near the roots of the plants.

This probably doesn't answer your question. :-) I'll try to suggest something more specific once I know what type of castings/compost you want and how much time you want to wait.

Andrew

You could try adding something to dry out the castings. That is try putting several hole (un-shredded) sections of newspaper in the bottom of a bin and put some castings on top of the paper. The paper will pull a lot of the moisture out of the castings. If the castings are very wet you may have to do very small batches. And allow the paper to dry out between batches. Unfolding the paper and hanging it up will dry it out faster. I'm afraid that will mean hanging it up inside in North Wet Washington.

If you keep using the same paper it will be full of good microbes and can be shred up later to make bedding for the new bin.

I am not to particular about the coarseness of the castings. I did add some more paper and it seems to be putting me on the right track. What is the onion bag method for castings?
Thanks in advance.

The onion bag method is a way of attracting worms out of the bedding. You lay down some sort of screen--an old onion bag, for example--and feed on/in the screen/bag. The worms will migrate to the food, and can easily be removed by lifting out the screen.