After drinking the water, cut the top off one of them just past the point where its shoulder begins to widen. Then cut the other one lower down. Your decision on where to cut depends on the length of your loaf of bread.
Slide one half into the other and there you have it: an elegant see-through, water-resistant bread container. If you want a matching bread bin for French loaves, you can make one as long as you like from a number of plastic soft-drink bottles. You can even create a telescopic, slide-and-fit effect.