Last week we did a job for our customer. Unfortunately we couldn’t clean one particular window, which had sparks on glass. Probably the most annoying of all damage to glass is weld or grind spatter. Not only because it takes twice as long to repair as any other form of scratch or mineral damage, but because there is no reason for it to happen in the first place. If contractors were grinding or welding close to a wooden floor, they would take measures to protect it, so why not glass. When using a grinder on metal, sparks fly off the metal with considerable force. These sparks contain tiny particles of metal that have been removed from the object being worked on. It’s very hot and hits the glass with a speed. Because of the heat and force, the metal particles can embed themselves into the glass.