Over time, natural beeswax crayons will develop “bloom” – this is actually an indication of quality, rather than being a problem!
Fully developed bloom looks like dust on the surface of the crayon – it doesn’t make the crayon toxic, nor does it change how the crayon draws.
To remove the beeswax bloom, simply polish the crayon with a soft dry cloth, or a blast of hot air from a hairdryer.