How to clean childrens foam floor tiles

[stressed2007]

I have a large room where the whole floor is foam squares with letters on them (concrete floor underneath and this was to cushion any fall). They are getting quite grimey despite mopping etc. Does anyone have these and a way to keep them clean? Thanks very much

You need bathroom cream cleaner - like Cif.

But don't scrub too hard - the letters will come off.