What is the best way to clean grout to make it white again without removing it and regrouting
Try one of the many Grout Restorers or Rejuvenators. They would bring the problem area(s) back to matching the rest of the grout. There are also Grout Coloring Kits that basically paint or stain the grout. You can luck out if a color perfectly matches your grout, but usually you'll have to do the whole floor's grout lines for everything to match. Sealing your grout is the only preventative measure you can take to avoid future situations. This paints on a clear coat &amp; thereby removes grout's porosity. Though, it does need to be re-done every 3 to 10-years...depending on traffic.