But the more effective way is to use entirely new tinted grout.
Remove grout from bathtub.
Once a day has passed the grout will be cured and will no longer be removable with water.
Steps to remove the grout.
Many people use a razor blade for this purpose though you must be careful not to scratch the tub.
If you see mold forming around where your floor and tub meet treat it with a mold killer after removing the existing caulk or grout.
Grout and mortar are not water soluble so the soak and scrape method as you might do for drywall compound will not work here.
In many cases it is faster and easier to remove the grout than to clean it.
The water will soften the grout again allowing it to be wiped away.
The blade is harder than the grout and will cut it away image 1.
One way to change grout color is to colorize existing grout.
This might include any grout along shelves corners and floor tiles or the grout and tile that surrounds the shower drain.
For much larger areas use a rotary tool image 2.
The existing grout color is no longer pleasing to you and you wish to change it.
Allow the paste to set for a few minutes to work its magic and then give the grout lines one more agitating scrub for good measure.
If this is the case it will be necessary to scrape it away.
If the grout is fresh it can be wiped with a sponge moistened with water.
Perhaps the grout is old and is peeling discolored or cracked then that is a good reason to remove grout.
Therefore in addition to removing the mess from the tub your aim is to minimize any damage.
Clean the surroundings of the bathtub.
When that day comes remove the grout and replace it to rejuvenate the installation and make the surface gleam.
For small areas use a grout removal tool with a carbide blade.
The old grout might be moldy and beyond cleanable.
Grout is made from water cement and sand which hardens over time to form a rock like material.
When you grout bathtub tile you do so in order to protect the wall that is behind it from moisture but sometimes you will have to or want to remove grout.
Make sure the bit is the right size for the space between the tiles and adjust the bit to the proper depth.
Next rinse the area thoroughly and use a cloth to wipe the surfaces clean.
Let the area dry the area for the minimum of what the moldicide recommends which is usually at least 24 hours before applying new caulk.
When remodeling a bathroom or kitchen the hardest part can be removing the grout from pre existing tile.
Steps to repair grout around the bathtub.
Remove and replace grout even the best tiling jobs show their age eventually.
Also grout and mortar are gritty and can scratch the polished surface of a bathtub.
Work slowly image 3.