spalding brick is due to maybe a number of reasons, poor manufactureing, freeze and refreeze of water penatrating the brick surface, byproducts and acids, that why sometime you dont want to acidize your bricks, use a detergent instead. now to answer your question. you can fix this by higher a knowegable brick contractor someone whos older perhaps. he should either take out the brick and replace it with new brick that matches close as possible, bricks in kilns are usualy a shade or 2 off. or the brick isnt made anymore. look at this website www.wendlandmasonry.com check our the brick problems page.