'Traditional' glitter is made of teeny tiny bits of plastic. So when glitter is stuck onto a card, daubed on a picture, painted on a face or washed down the drain, it doesn't go away. It enters the wider environment (usually either ending up in the oceans or in landfill) and lingers for hundreds of years - eek!
'Biodegradable' glitter is available to buy, but there is some evidence that even this 'eco' glitter can contain trace metals (for sparkle) and tiny amounts of other long-lasting nasties, which enter the food chain despite us using it in good faith.
So why not play it safe and use 'sugar glitter' for crafting projects / face painting?
Either, mix white granulated sugar with a drop(s) of liquid food colouring (or use gel food colouring, but it is much harder to stir in), spread out the coloured sugar on a lined baking tray, bake in the oven at 180 C (160 C fan) or Gas 4, for 3 - 5 minutes - until dry but not burnt / melted! Be warned - it comes out of the oven much lighter in colour than it goes in. Allow the it to cool for 10 minutes and then scrunch the coloured sugar up into tiny pieces and store in a air-tight jar for up to 1 month.
Or, you could just glue (straight from the packet) white granulated sugar on top of dry paint / crayon / dry pen colouring-in, to get sparkle and vivid colour. The sparkly blue star in the picture above is simply blue crayon colouring-in, with sugar glued on top. The Coccoina glue tin is a plastic-free alternative to Pritt Stick (but it contains a trace of almond nuts and the teeny-tiny brush has pig-bristle hairs - so it isn't suitable for everyone).
Yes, this homemade sparkle won't last forever, but I think we all now realise that this is a good thing when it comes to glitter.