How do I clean this tile mess up?

[Anonymous]

My son was trying to help fix the tiles and he did but he made a mess and it’s dried up

[EmmaMary]

To make a mess like this, just how old is your son?

[EmmaMary]

Thank you for the A1 BC.

[andreasderjuengere]

If this is cement, I'd use hydrochloric acid.

Needless to say that this is dangerous in the hands of an amateur.

[JaxiCats]

Have you tried cleaning supplies?