Paint with water (and food dye)
Make some water based paint which is easy to use and safe to play with.
Ice cube tray
Paddle pop sticks (or similar)
Mix water with food dye and fill a ice cube tray with each colour
Place paddle pop sticks or other sticks for handles in each ice cube cell
Freeze for 2- 4 hours
Best to use the ice paint on water colour / thicker paper