You can take the mirror glass and back plate off

by pulling it. you need to put some black "glass glue" between mirror glass and back plate. Use duck tape to tape around edges for 3 days.
Is your side mirror heated? If not, you can order a after market one through your local window glass shop. Most of them will do free installation. The mirror glass will cost you about $40-$50 each. You need to buy curved one for passanger side.