Perform a dutchman repair by replacing individual spalled or damaged bricks with matching salvaged or reproduction brick

Steps

1. Identify the full extent of damaged brick requiring replacement, checking for hollow-sounding or cracked units beyond the visibly spalled ones
2. Source replacement brick that matches the original in size, color, texture, and (ideally) firing/hardness characteristics — reclaimed brick from salvage yards or the same building's non-visible areas is often the best match; new brick rarely matches historic units without careful selection
3. Carefully remove the damaged brick and surrounding mortar by hand or with minimally invasive tools, preserving the opening's original dimensions and avoiding damage to adjacent sound brick
4. Test-fit the replacement brick dry before setting, trimming as needed for a tight, consistent joint width matching the surrounding wall
5. Set the replacement brick using a mortar mix matched to the historic mortar (see mortar-matching guidance) rather than whatever mortar is convenient, and tool the joint to match the surrounding profile
6. Where an exact salvage match cannot be found, consider a compatible reproduction brick or, for a highly visible location, consult the preservation architect on an acceptable near-match rather than proceeding with a visually jarring mismatch