Painting with Little Children

One of my biggest problems when painting with my children is the paints either spilling or getting mixed up.

We recently started using egg cartons to divide the paints up and it has been quite effective. I put a squirt of each colour in to the bottom of the cups and then the kids can use the paints. I make sure that there is a container of water. So far we have avoided mixing the colours up, and this is after the children had been painting for almost 40 minutes uninterrupted.