...I had an idea that I could create "mini-greenhouses" from the plastic bottles. I.e., cut them around the middle to be left with a plastic dome and pop that over the top of the seedlings to provide them a little protection in the first few weeks until they're established. Multi size bottles...
Oatmeal containers: Chick playgrounds! You can cut the end off to make a tube, place in brooder, and the chicks will race around and play hide and seek in them. Toilet paper tubes work for quail chicks too.
Coffee cans: punch a few holes in the bottom, cover in light paint if you want, and...