Reusable zip-top bags?

Last night I was teasing my mother-in-law. She is not green. Not at all. She told me, as she has before, that she uses zip-top plastic bags for everything. She said, in fact, that she "uses them like water." I use them to. (I say, ducking the bullets) It's a major thing I need to change. Anyhow, so I was teasing her. I said I would need to create a reusable zip-top bag for her. I mused out loud, in a joking tone, about how I would do it. I've been pondering it ever since! Of course the green thing to do would simply be to find alternatives that are safe, reusable, and so forth. But you can lead a horse to water.... It would be a lot harder, I discuss with myself, to refuse to try something if it is basically the same product only safe and reusable. HM! Maybe waterproof diaper bags that people use for holding soiled cloth diapers when out and about. I dunno. This has become a challenge I may just take on. I happen to have some PUL (water-proof) fabric in my stash. Is that safe for food? I'll need to research that. The best way to influence people is to teach by example, so maybe I'll see what I can create for myself, and if they work, I can slyly introduce them to MIL and others. =)

I might try this tutorial , if PUL is safe for food. I would be using PUL instead of the plastic this calls for. I have PUL in my stash, for one thing...

Just a quick online search on PUL safety for food storage has me believing that it has not been approved. Darn.