I have this mirror that I am replacing. This mirror was extremely heavy and fell off the wall one time and the frame is broken. The mirror/glass part is all in good shape. The edges are just sharp and it's heavy so I don't know how to dispose of it. Or where I can take it.
Craigslist (or equivalent) "free mirror, broken frame" with pictures. Or a low price, which sometimes works better than free even without the aspect below...
Set beside the street, sign "free" (if that does not work, set a price and hope someone steals it now that it has value, or be pleasantly surprised if someone actually pays the price. Or just start there.)
If you just want to trash it, the easiest way is to break it up small enough to fit in a trash can. Lay it down and cover the front with packing tape, then go at it with a hammer or crowbar (wear gloves, heavy jeans, closed toed shoes, safety glasses, and ideally a hoodie with a high neck). Take it slow, break it and put into a trash can. The can will be HEAVY by the end, so you might need a couple.