Chinchilla safe colours/dyes?

I'm picking up the boys' new chinnie cage on wednesday but I'd like to brighten it up a bit by staining/dying the shelves different colours.



Does anyone know what is safe to use? I've heard food colouring, confectionery paste (although not sure where to find this) and even tempra kids paints are suitable but wondering if anyone has experience with this? I know pet shop toys are coloured with vegetable dyes but again I can't find a supplier that specifies if theirs are pet safe.



If anyone can help with this I would greatly appreciate it :)