On Sep 9, 5:49*pm, bill jensen wrote:
wow! *Is there anything that will remove it? *I've tried bleach,
cleanser and even Goof-off with no luck. *I think a wire wheel may do
it, but it's a broom finish and i don't want to knock that off and leave
smooth area. *fyi, the slab is just 3 days new so I've been holding off
on acids.

* Any ideas appreciated.

Do you mean chalk...... like chalkline chalk?

If so, ignore it. It will wear off in time.
I believe there is a high potential for doing permanent damage to your
"green slab", let it cure.

cheers
Bob