How can you clean old dried out grout from a shower and tile floor.

Use warm water and wipe it over the surface of the tiles with a sponge. Then using some fine wire wool, rub gently over the grout which will begin to dissolve and rub off at the same time. Once the tile is clean and has no more hardened grout, wipe over with a damp cloth and leave to dry.

get a grout removing tool, scrape it out and regrout.

Go to Homedepot or Lowe's and ask in the plumbing dept. I try to use Kaboom foam, or make a paste of baking soda and vinegar. Leave on for a couple of hours, and scrub with a stiff toothbrush, if you can find one. Good Luck!

I saw a grout-removing tool being used on HGTV on one of the house flipping shows. It looked like a large seam ripper to me. It grabbed under the grout and tore away the old, grimy grout in long strands. In those able hands, it took seconds to strip a shower or sink, and less than a minute for a tub. Cleanup was the same as any job. Use fine steel wool or a stiff brush plus a cleaning spray to get off the rest of the grout. Use Goo-Gone for really sticky or tough areas. Let the clean tile and shower dry a day if possible before you regrout. Best wishes 😇

I used barkeepers Friend on my grout it cleaned it bright again ! Use the one in spray bottle ! I used a grout brush and it turned out amazing ! Hope it works for you

I found some grout paint on Amazon. It works really good!