I found this idea over at Unplug Your Kids a long time ago.
This week I had some past best before date rice and this craft came to mind.
Pour Rice into Zip Lock Bags and add a few drops of food colouring
Get Kids to squish and sqeeze bags to spread the dye.
When you're happy with the colour place in foil lined oven trays and bake for 10-15 mins.
I think the baking sets the dye, so it doesn't stain your hands.
My favourite was the bag I put a drop of each colour in.
Use rice in sensory tubs for kids, in crafts, line bottles (like coloured sands) uses are endless!