You can open it all up or leave it as is for your needs. Here in Pookieville we use these bags in place of wax paper. Although, I probably wouldn't bake a pumpkin roll on them. I freeze Grandma Kahn's Perfect Pie Crust in them. When it's time to roll out the pie crust, I use them then as well to roll it on. I've cooled caramel popcorn on them. I've also cooled granola on them. mmm... granola.
I have also frozen brownie bites, muffins, and cookies in them.
And on occasion when I use disposable diapers, I've thrown a particularly stinky diaper away in one and put it in the kitchen trash so I didn't have to brave the 10 foot walk to the trash can in the bitter cold. Wrapped in the cereal bag it blocks the smell a lot better than a grocery plastic bag from somewhere like Ooh-Mart.
I am ALWAYS on the lookout for more ways to recycle things and be frugal. I would love some more frugal tips. What do you do in your home that's frugal?