Tile backsplash?

Try some rubbing alcohol on a cloth. If that doesn't work, hydrogen peroxide may.

Make sure all the grout is off and if there is staining use a Teflon safe scrubber with lemon juice or hydrogen peroxide to remove the color. Be careful not to get on the grout and make sure it is sealed before starting to clean.

That’s an interesting question. I wonder if all chemical cleaners are ineffective if using a grout saw with a very light scrubbing action would help remove the painted layer.

Here's a helpful link:

https://www.wikihow.com/Clean-Grout-Off-Tile

If it's just a coloring try rubbing alcohol or nail polish remover

Hi Bob, hope this helps Mix equal parts bleach and water, apply it to the stain, and let the formula sit for around 10 minutes. When you wipe the bleach away, the stain should wipe away with it.

Instead of removing it perhaps it would be easier to just color what is there since you can make it the shade you are interested in.

https://www.youtube.com/watch?v=9QwXrppyvOc

Here's a post that might help https://www.bobvila.com/articles/how-to-change-grout-color/#:~:text=Pour%20a%20homemade%20paste%20of,ready%20for%20a%20color%20change!

If it the the dye from grout coloring use Awesome spray cleaner from the Dollar store. There is nothing I have found that it doesn't work on like no other product.

You could paint over it to change the color

Acetone, not nail polish, the kind that comes in the blue can at lowes will work.

You might be able to buy a tile cleaner from the tile shop!