I have antiqued mirrors and removed the silvering from mirrors and the chemicals are dangerous and caustic. The bottle "smokes" when you opening it, you have to wear heavy utility gloves and should wear a respirator. The vapors can burn the mucosa in your respiratory system.

I have only done small pieces. I think you would need to do something like this outside with a plastic wading pool for a larger piece.

The mirror place I use charges by the square foot for antiquing, offers a variety of levels of antiquing and it's expensive.

How about a photo of your mirror?

Good to know. Thanks!