You can't line the floor of any oven without having problems

Our manual says the same. My wife and kids laugh at me, but when I put a pan or foil on a rack a slot or two below what I'm cooking I call it a "diaper".

What's the best way to removed cooked-on messes from oven racks that can't be left in during self-cleaning?

My grandmother cleaned oven racks by placing them in a trash bag of appropriate size and tossing in a dose of ammonia, let site overnight, or longer as needed.

A bad idea, yes, but I doubt it would make the floor of the oven warp. No way can a piece of aluminum make hot hotter.

Dadoes is correct. Ammonia works well. I soak paper towels in ammonia and leave them lying on the racks for a couple of hours (out on the patio) but it's mostly elbow grease. But I really only have to do it once a year, if that. I'm careful to not overfill pans or baking dishes.

Aluminum foil reflects heat back at the element as well as conducting heat away. Since foil has so little mass and is so close to the bottom element, it contains the heat and that starts to damage the finish. Then the foil melts and really messes things up.

I wonder why oven appliance makers don't simply put an eye catching warning sticker in their products. Something like: Don't put foil here you lazy, illiterate, ----.

Rather than call the costumer names, it would be nice if they could figure out something like a silicone mat that can be popped out of the bottom and easily cleaned.

I know I'm a guy, but I have to ask why one would put foil inside a self-cleaning oven?

You line it so you don't have to use the cleaner very often. In older ovens, that were actually made better, it wasn't a problem, but these newer models, you can't do it. My manual also says to not do it, and also don't get it on the stovetop, it will melt.

They sell silicone liner mats for the oven floors. I personally don't line my oven and never have. If I have something that will potentially boil over, I put it in a large clay pan to catch the drips. If it does drip, I use a wet rag to clean the bottom while the oven is still hot. I also put hot water in my oven to loosen up the tough bits and just wipe it down instead of running the self clean.

Good luck!

Hi,
I have been searching high and low on the internet to see how to clean off the foil from the bottom of my ne GE Monogram oven. (I found your forum on Garden Web) I like your sister thought it was the right thing to do...protect the bottom from dripping cheese off the frozen pizza. At first I thought that the foil was my only problem and then this morning I noticed the bottom of the oven was warped. GE is sending out a service technician next week.
I was wondering if your sister had to pay for a replacement or did they handle it under warranty? Also if you could tell me anything about your sister�s experience that you think would be helpful? My concern is they say the damage is not covered since I put the foil on the bottom. Interesting note, I only used a small amount of foil and it was on the bottom loose. I am amazed that an expensive oven would be so sensitive and that they would not have put a large sign somewhere that states: "do not use foil on bottom of oven as it may cause serious damage to your new oven.
I really would appreciate any insight you could offer.

Removing burned-in aluminum foil is going to be tricky. You can try to scrape it off, but that might not work. And it could cause even more damage.

If it doesn't work, harsher chemical methods might be needed. In most likelihood, your oven is coated in enamel. That's good. Enamel is immune to acids (but not necessarily bases). And aluminum can be dissolved in acids.

I wouldn't do this in the oven, but if you can remove the oven floor, see if you can soak the aluminum in a medium-strength acid. Distilled vinegar (and lots of time) should do it. Or if you are impatient, diluted muriatic acid. Wear gloves and goggles and do this outside. The fumes aren't good for you (for neither chemical). But other than that, the chemicals are comparatively harmless. Rinse with plenty of water when done. Similarly, rinse with plenty of water, if you do get any on your skin. And absolutely don't get either acid into your eyes, of course.

The only tricky part is that the floor panel might not necessarily have a good enamel coating everywhere. So, you probably don't want to dip all of it into acid. If there is exposed metal, it is OK to get some acid on it; but you don't want to expose it for hours on end. Maybe, use some type of putty (plumber's putty, playdough, hot glue?) to build a temporary ridge around the affected area and only fill that area with acid.

If you live in a sunny part of the country, set the oven floor outside into direct sunlight. The warmer the acid gets, the more quickly it'll work.

Of course, while this is a good way to remove the burned-in aluminum, it won't do anything about the warping. And if the enamel is already cracked, I wouldn't recommend this approach. You don't want the acid to seep through the cracks.

And in the future, do what others have said and instead of aluminum foil, use a cookie sheet.

Do not, DO NOT, DO NOT place foil on the bottom of an oven that 1) is electric and has a heating element under the cavity floor, 2) that is a self-cleaner with an exposed bottom element unless the foil is removed before running a clean cycle, 3) covering the heat vents of a gas oven.

100% agreed with @dadoes, there really is no good reason ever to use aluminum foil, when cookie sheets are so much easier to deal with and easier to clean as well. They also contain bigger spills much better.

Also, absolutely agreed that even with a cookie sheet you have to be careful that you don't cover vent holes. And depending on the exact design of your oven, you might want to set the cookie sheet on the bottom-most rack instead of the floor of the oven. That's hard to give generic advice for.

In my particular oven, setting the cookie sheet on the very bottom is OK. It results in minor discoloration of the enamel, but no other damage. It also results in more even heat distribution. But just because it works for my oven doesn't mean it'll work for anybody else. Setting it on the bottom-most rack is definitely the safer solution.

Most modern electric ovens, the ones with the hidden elements, should never have anything, including silpat, foil or cookie sheet on the floor of the oven. You also shouldn't wrap a rack with foil, but a loose piece of foil that allows air circulation around it on a rack, or cookie sheet on a rack, should be fine.

Extra racks should be available from the maker or through your appliance store, and you can often find generic replacement racks that will fit well enough for the purpose.

This happened to me last week. My husband placed one of the silcone non-stick liners AND aluminum foil prior to reading the directions/warnings that I asked him to. So, we now have a completely discolored bottom pan that also warped. We called GE and they said the pan cannot be replaced. This oven has never even been used... $2000 oven and no way to replace the part. Sick to my stomach...