Plan ahead by working with the demolition company that is removing the building. Get permission to remove the blocks and find out the times you can be on site. Wear proper safety equipment such as a hard hat, goggles, gloves and dust mask. Plan every move you make, being careful not to work under dangerous overhanging debris or to walk on unstable surfaces. Make sure you are not removing blocks from a load-bearing wall. Safety is the number one priority when salvaging antique concrete blocks.
Remove and stack any blocks that have fallen off the building due to demolition from the wrecking ball. Use the bristle brush to clean off loose mortar pieces. Separate complete blocks from slightly damaged blocks that will need to be patched later. Because of the age of the mortar, some blocks may break away from the mortar cleanly.
Score the lines of the mortar around a block that you want to remove from a wall with the masonry chisel and hammer. Be careful not to damage the edges of the block as you chisel these lines.
Cut through the scored lines all the way around the block with the circular saw. Continue to cut over these same lines all the way around until the maximum cutting depth of the saw is reached. Repeat this same cutting process on the opposite side of the block if it is accessible.
Break the mortar lines all around the block using the chisel and hammer.
Loosen the block by placing the wooden board against the side of the block and hammering with the rubber mallet.
Continue the process of cutting the mortar, chiseling and hammering until the antique concrete block has loosened completely. Remove and clean the block with the bristle brush and stack with others.