In my youth I did a lot of fishing. We always had minnow traps set out to catch bait. It never failed I would always have crawfish in with the minnows. All we did was take a quart canning jar and a piece of screen wire shaped like a funnel stuck with the small part of the funnel down in the mouth of a jar. Bread, bacon, chicken necks would work well. I saw on here earlier how to make a minnow trap out of 2 drink bottles, I can see where that would work great and will try it soon.