Do they put something in the glass containers and the wasps go in and cannot go out? If so, why couldn't you use a 1 liter bottle? I suppose you put something meaty or something sweet in them.

I take the two liter pop bottle, cut it about an inch under the top rib. Making basically a funnel. :-)
Invert that into the bottom part, staple together.
Be sure you get it as close together as possible, if not just put a little tape around the top to close it so they can't get out there.
Put/staple on a string to hang, making sure it goes through the two pieces. Add about an inch or so of sugar water.
They can get in but can't get out. Every year I have about 3 green "bottles" placed around (a distance from where we are), they for some reason are more attracted to the green
bottles.
Worked ever year so far and oddly enough I have never found any honey bees in there.
Hope that helps. :-)

this might cost some money, but, abc distributing has them for only 6 bucks, and they look nice too! i know thats not exactly 'free' but, that is cheap.

Blessed Be,
Carrie Ann

Thanks for the lead to ABC distributing! Similar items elsewhere were pretty pricey. I went ahead and ordered several to put aroung our property.