Move furniture away from the glass block wall or window. Place drop cloths over the carpet and furniture you are unable to remove. Removing grout mortar is a messy job that will cover the room in a layer of dust.
Put on gloves and goggles to protect your eyes and skin.
Position the cold chisel on the layer of mortar between the glass blocks. If you are dismantling an entire glass block wall, begin with a glass block on a top corner of the wall.
Tap the end of the chisel with a hammer several times. This will dislodge the mortar. Repeat all of the way around the glass block to remove it.
Repeat with all of the other glass blocks.