If he didn't say it - he should have, truer words were never spoken.
On a mess scale of 1 to 10 chalk paint rates about a 9.5 but on the other hand the clean up is only about a 3/10, tops.
I got the girls to mix up some corn flour and water, we used about 500gms of corn flour and enough water to make it nice and runny. Then we divided it into a paint tray and added red, blue and yellow food dye. Then we mixed the colours together to make other coloours and the girls had fun guessing what colour would appear.
Then I just let them go nuts painting on the pavers out side with paint brushes. They came up with ways to make all kinds of patterns - splatters, drips, lines, as well as painting pictures. Evie found a stick and did some great dot painting, and ofcourse Georgia painted her toes!
When they were done I just hosed off the paint trays and brushes (and the kids) and later hosed the paintings off of the pavers too.
The girls did get quite a bit of paint on themselves but thankfully it came off their clothes in the washing machine and off them in the bath (except some purple toes which took a day to fade)