I would keep them on nothing. A cheap empty plastic bin from Wal Mart is perfect for them, just make sure they can crawl around on egg crating, paper towel or TP rolls, and they'll typically do ok. When you clean the bin, just throw everything away, clean out the bin with hot water, let dry and start fresh, ideally with new rolls or egg crating. Keeping them slightly warm (80-85) helps keep them alive, and it's the dead crickets that really end up smelling. Try cleaning once a week, or buy less crickets, so they're all gone before you need to clean at all. Keeping a vented lid (with 50 percent or more of the top replaced with aluminum screening) will keep some of the smell in, but when you open it up, ii'll smell really bad while the lid is open. It's probably best just to leave the top off, and keep the container clean and well ventilated. Also, buying crickets from a source with no "pest bugs" will help keep them alive it seems. Once those fuzzy little black worms get going, it seems that cricket groups die off fast. I seem to have the best of luck so far getting crickets from Wormman.com. Good luck!
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Tyler Stewart
Las Vegas NV
www.BLUEBEASTREPTILE.com