I use cubes of floral foam. Soak the cube full of water and cover it with plastic wrap like it's a present. Then insert the cuttings into the foam. This is a method I read about on this forum and liked the idea. It works pretty well to keep the cuttings fresh and the plastic wrap keeps the water in.

Sometimes I do cut a large single leaf and put the stem in the cube.

I use large yogurt containers, cut "x" slits in the top and insert. The milkweed lasts 3 or 4 days that way, if they haven't eaten it all.

Have fun!

My first monarch cat is getting ready to pupate now, and the method I used was, for the first two instars, I kept the caterpillar in a shallow tupperware with a moist paper towel at the bottom. I would then place a fresh leaf in every day. Once he reached the third instar, I took a plastic water bottle, covered the top with duct tape and poked a hole for the milkweed stem. I don't know what milkweed species you have, but the tropical milkweed stayed fresh very well, just make sure you rinse the sap off the bottom when you cut. This probably won't work for many cats, but I think it could work for just five. Good luck!