Bad luck or not, sometimes a mirror must be broken. Large bathroom mirrors are notoriously difficult to remove from walls. Often you must break the mirror and remove it in smaller pieces. Some craft projects require you to break pieces of mirror from a larger piece. Since mirrors can break into dangerous shards that can cause serious eye injuries and cuts, you must exercise caution when breaking a mirror.
Put on gloves and safety glasses.
Place a tarp under the mirror.
Score the mirror into sections with a glass cutter.
Place strips of duct tape on top of the score lines.
Cover the mirror's entire surface with carpet protector film, which is available at home improvement stores.
Tap the mirror lightly with a small hammer along the duct-tape covered score lines until the glass breaks.
Remove the carpet protector film and duct tape carefully if you're reusing the mirror pieces.