Removing red chalk update

[Greg]

This went on for a week or so, here is what I found. I had some on concrete in a place where I could experiment. Pressure washing was largely ineffective. I suppose eventually it might do something. Bleach was no good. The thing that works instantly, muriatic acid, cut about 4:1 with water. Using that as a guide I figured out "Lime away" will also work but it requires a little scrubbing with a brush. That is a less aggressive chemical. CLR would probably do the same.

[bumtracks]

Thanks ! Next time I feel the need to buy some red chalk & draw on the sidewalk, I'll try to find some of that stuff first. Will it work with white chalk too ?

[Greg]

This refers to red chalk line chalk, not the sidewalk variety.