Water soluble wax crayons contain an emulsifier wax and polyethylene glycol. Molded crayons contain lower m.p. waxes. Extruded or pressed crayons have more filler and are more dense, i.e., Kantrolls are three times heavier than molded crayons. Oil penetration and haloing over time. Efflorescence or wax bloom may be present.
Many colors are light sensitive.
I crayons exclusively. Crayola estimates that by the age of ten, every American child has worn out 270 crayons. A Yale University study ranked the smell of Crayolas among the 20 most recognizable scents in America. In the mid 1920s, Binney and Smith introduced Munsell Perma Pressed Crayons which, along with Crayola , conformed to the Munsell Color System. The product was part of an educational campaign imitating western art education, aimed at elevating children's creativity by providing vivid colors in soft stick form.