Reusing old brick is an ecologically friendly way to conserve energy and help the planet. The reuse of old brick reduces the environmental costs of new brick manufacture and old brick disposal. Unlike recycling, the reuse of a product means to use it again for the purpose of its manufacture. To reuse old brick you need to make sure it is fit-for-purpose, using a procedure to help you determine the outcome for the old bricks.
Sort the old bricks into piles to determine the quantity of reusable bricks you have. Use one pile for full-size and sound bricks; one pile for full-size but chipped bricks; one pile for half bricks that are structurally sound but broken, and one pile for small brick pieces and brick chips.
Check how many structurally sound bricks you have to determine if you have enough for a reuse project you want to do. Decide on a semi-hidden project if you have a lot of chipped bricks, such as building a low wall to create a garden border. Your planting will overhang the less aesthetically pleasing bricks. Decide if you have enough sound bricks to create an on-show project such as building a permanent barbecue.
Wet the old brick that you want to use for your project, using a garden hose. Fill a bucket half-full with water. Fill a second bucket half full with a solution of one part muriatic acid to 20 parts water.
Use the wide end of a brick hammer to knock large chunks of mortar off the old brick. Use the narrow end of the brick hammer to scrape off smaller mortar pieces. Place the brick in the bucket of diluted muriatic acid for up to 5 minutes to chemically dissolve the mortar bond.
Put the soaked brick into the water bucket and use a scrubbing brush to vigorously clean the mortar residue from the brick. Rinse the brick with a garden hose and allow it to dry. Repeat the mortar removal and brick cleaning procedure for each old brick to make it fit for reuse.
Build your project reusing the prepared old brick. Reuse broken half bricks for end gaps in a staggered wall and chipped bricks in areas not on show. Recycle the pile of small brick pieces and chips for use as aggregate in paving projects or for planter drainage.