When installing a brick paver patio it is common to get cement coloured grout or mortar on the surface of the brick. If you notice the grout or mortar while it's wet, removing it is as simple as wiping it up with a clean damp rag. If the substance dried onto the surface of the brick, you must use alternative methods that will require a labour intensive repair.
Hose down the brick with a hose. Water acts like a lubricant and helps avoid scratches to the surface of the brick.
Chisel away the excess mortar or grout with a hand chisel and a hammer. Work to keep the chisel off the surface of the block to avoid cracking, scraping or scratching the block. As you work, keep hose water flowing over the work surface.
Wipe away the loose mortar with a broom and clean it up with a dustpan.
Dilute 1 part muriatic acid with 10 parts water in a plastic bucket. Place the solution onto the cement coloured residue with a wire brush. Allow 15 minutes until you move to the next step.
Scrub the mortar or grout with the wire brush and then spray away the remnants with the hose. The more water you use to rinse the acid the better for the brick and the vegetation around the patio. Repeat Steps 4 and 5 until you remove all of the excess mortar.
Follow all precautions listed on the packaging when you use acid to avoid injury. Allow two weeks curing time if you allowed the mortar or grout to dry on the pavers. This will prevent the acid from hurting the mortar or grout you intend to keep.