Re: Mirror Removal
The staining that you're seeing is likely a result of the glue reacting to the silver coating on the back of the mirror.
I absolutely HATE glued mirrors!
First and foremost you absolutely must wear protective clothing, gloves, and safety glasses! Glass is nothing to be trifled with, especially when the likelihood of breakage is extremely high! You want long sleeved shirt, leather work gloves, safety glasses or a face shield. You'll want to clear the clutter out of the room and cover the sink/counter with a heavy blanket topped with a tarp which will catch most of the glass should the mirror break while removing it.
There will likely be a couple of clips at the top and sides of the mirror that are screwed into the wall. Remove them. You will need a flat pry bar or two such as a wonderbar.
You will be prying along the edges of the mirror very gently to try and get it to release from the glue/wall. If you're lucky the mirror will release intact. Most likely what is going to happen is the glass will shatter - hence the protective clothing. Regardless, you're going to continue prying around the edges until you get the pieces off the wall.
An alternative would be to cloak the mirror with the tarp and blanket and smash the mirror with a hammer, then pry off the pieces. This is actually a much safer means of dealing with it, then you're not going to be injured by an unexpectedly shattering piece of glass.
I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!