Replacing the old grout requires scraping it out to a depth of at least a quarter of an inch, and then troweling in new grout.

Scrape out the old grout to a depth of at least a quarter-inch and make sure that no dust or crumbly material remains.

Scrape out the old grout to a depth of at least a quarter-inch before applying the new grout.

You needn't remove all the old grout, just the stained or crumbled portions to a depth of approximately one-quarter inch.

To correct the problem, you must first remove the old grout.

Dremel grout attachment an attachment guide used in a die grinder for faster removal of old grout than a standard grout saw.

Dathim picked up an abrading cloth and wiped it across an area of the wall still rough with old grout.

I have tried various cleasners and tile cleaners, including one for removing old grout, but nothing has worked.

If the grout is starting to crack or crumble, it should be replaced, but first you'll have to remove the old grout.

A grout saw has a short carbide-tipped blade designed to rake out the old grout.