Foil stuck to bottom of oven

A bit of chemistry first. Aluminum foil reacts to acid. A black substance referred to as aluminum salts is formed. This is simply wiped away. How quickly the foil is converted depends on the strength of the acid. Vinegar has a safe level of acid content. Within two hours, some aluminum salt should have formed. Wipe it away. Repeat. And keep repeating until all gone. Yes, the process takes time but you can be doing something else. And the salts are black, so you don't want your clothes or hands covered by the black. Expect this to take a long time. And you may get frustrated and decide to buy a new liner! But if you work at it long enough, it will remove the foil. You may be pickled by the end of the process but repetitions of this will remove the foil ... in good time ...with enough applications and wipings. And you haven't been exposed to fumes or effects of sodium hydroxide.

Hello, Ofelia816 -

I found the following information on an LG web page,
< http://www.lg.com/us/support/answers/ranges2015/gas/optimal-setup >
[Quote]
Do not line the oven walls, racks, bottom, or any other part of the oven with protective liners made of aluminum foil or any other material.

Despite widespread use, these liners are actually quite dangerous. They can disrupt heat distribution, produce poor baking results and cause permanent damage to the oven interior (aluminum foil will melt to the interior surface of the oven). Improper installation of these liners creates a risk of electric shock or fire.

Luckily, your LG oven has a "hidden bake" feature that conceals the heating element. This makes cleaning much easier and eliminates the need for any sort of a liner.
[End quote]

Bottom line:
It seems you will have to live with the horrible look of the melted foil . . . and probably replace your LG oven or have it repaired much sooner than you expected.