Instruction: Given a question and the related document, and generate the answer to the question based on the information provided in the document.

Input:
Question: what is the bag made of?  Safety issues
Document: These "Toastabags" actually work very well for making grilled sandwiches in the toaster and have the added benefit of being washable and reusable, but there are durability issues. My wife picked these up on sale at a kitchen specialty store to try out since we eat a lot of sandwiches.These bags are made of a nonstick material that easily holds two slices of bread and the sandwich ingredients of choice. Once assembled, we apply spray butter to the outside of the bread and insert into the bag.
Yay, love these. I took on vacation so I could have toast. Works great. I have also made hot sandwiches, bread,then mayo and turkey it does take 2 bags to make it all hot at once, but 3 come in the pack so it's all good.
I bought these for my wife, who loves grilled cheese. The bags are rather easy to handle, but tend to get a bit messy when you try to get buttered bread into them. I bought a Hamilton Beach Ensemble SmartToast Extra-Wide Slot Toaster to use with these and they fit fine. I didn't particularly enjoy the grilled ham and cheese made with these though. They probably won't last the 50 uses that they advertise, especially if you put them in the dishwasher.
Probably works even better with regular bread, but the fact it worked with our gluten free bread is just incredible to me.Each bag can do up to 50 sandwiches. It even heats up pizza but we haven't tried that yet. You'd have to cut your pizza to the size of the bag I imagine.Weeziesgfkitchen.com
This little bag makes lunchtime a snap! Just place 2 slices of cheese between two slices of bread, place sandwich in bag, pop  into regular old toaster and voila! A perfect grilled cheese sandwich without all the fuss, muss and butter!
Standard sliced bread, a few pieces of cheese and maybe one or two things like tomato slices and bacon, that's all you're going to fit into the bag.They do protect my sandwiches from being burnt and leave a nice brown on them. Can get messy on the bottom if your cheese drips. Washes out with plain soap and water, just be gentle with them.
Our 13 yr old was diagnosed with Celiac but we didn't want to have to buy a new toaster. These bags are working well - waffle still toasts and bag doesn't burn. We've reused the same one daily. It says 50 uses but I think it will be easier just to think of it as a monthly bag and just buy a new 3-pack quarterly.
Really convenient way to make a grilled cheese without the clean-up. You can even add other ingredients in-between the bread and cheese (I put apple slices, Yum!) and the bag holds everything together while melting the cheese and toasting the bread evenly. I use a toaster oven and it keeps the cheese from making a mess dripping everywhere.
My mom asked  for these for Christmas. Although nothing can replace a stove top grilled cheese (with tomato soup on the side), this comes close. it takes a couple of times to get your toasted cheese perfect. For those calorie conscious, spray your bread with PAM butter rather than regular butter or margarine. You can be creative and add meat or other items. Over time the bag darkens, but is still useable.
Just twist around a common expression and you've got it: Toastabags are the best thing next to sliced bread. No butter needed, no griddle cleanup, just nice toasty bread and melty cheese. Slice your cheese and any other fillings, pile it between two slices of bread, slide the pile into the bag, and in three minutes or so, a perfect toasty sandwich...  Fast food, at home, as healthy as you want to make it.
Answer: BOSKA website says they are made of woven fibre glass coated in PTFE (teflon)