Terracotta tiles - white marking

[scoobydoo]

I have terracotta tiles on my kitchen floor. A couple of them have a white scaling on the top. I'm not sure what's caused this as it was like it before I moved in. I can't get the white marks off - I've tried using a toothbrush and some acid stuff a tiler recommended but it seems to do nothing. It's a kitchen floor so needs to be sealed. I'd like to remove the nasty white finish and reseal the tiles.

Any advice on how I do this and any products I should try?

 

[Penners]

I wonder whether it's a slight damp bloom/efflorescence. Try treating it with white vinegar, which is a mild acid. Wash the vinegar off afterwards with a mild detergent solution.

Don't be fooled into thinking the problem has definitely disappeared until the tiles are thoroughly dry. Efflorescence can become invisible when it's wet.

Please let us know whether the above works.

 

[rebeccac]

I think I'm right in saying its best to dry brush the tiles then hoover off the dust!

 

[Penners]

No argument with trying that first.