As a kid, I used to cut the spout out of a 2-liter bottle and push what was left of the top down into the bottle to make a cone with a hole about the size of a crawdad. Then, poke holes all over the body of the bottle for some water circulation and attach a rope (so you don't lose it). Throw some raw bacon in it and submerge it.

I think we made one out of hardward cloth also.