Product review (5 stars): It's very helpful
I had one in my oven before buying these.  I have accidentally overfilled containers so when things baked, some of it ended up on the floor of the oven which these make for an easy clean up.  But I just did a HUGE faux pas when I took out my cookie sheet and didn't realize I picked up a magnetic potato chip clip and proceeded to cook it when putting the cookie sheet back into the over to bake my cookies.  If I didn't have one of these at the bottom, not quite sure how I would have fixed that issue.  I was able to pull out the sheet and toss it and put a new on in.  Bada bing, done.  Not butter knife, knee pads, turning the oven cleaner on probably more than once, and maybe just buying a whole new oven.  Love this product.