What is best/ easiest way to clean or make grout white again without removing it and regrouting? The grout is not chipping or missing. Remodeling hotel room
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 & thereby removes grout's porosity. Though, it does need to be re-done every 3 to 10-years...depending on traffic.
I wrap 150 AA grit sandpaper around a piece of plastic similar to a large stiff credit card. Sand the horizontal grooves, then the verticals. Re-wrap the sandpaper to get a fresh edge when it wears out. Wipe off the dust with a brush and fluffy towel. The difference is amazing. Then you can seal the fresh-looking grout.