What are Vitreous Enamel's superior qualities? Glassmetal Industries are proud to have been manufacturing the finest Vitreous Enamel products for over 100 years. When Vitreous Enamel is exposed to ultra violet radiation from the sun it has proven life span of at least four times any other metal finish. Vitreous Enamel is vandal-proof - almost impossible to scratch. Graffiti can be easily removed with solvent from a rag without any damage to the surface. Vitreous Enamel has the hardness of glass and the strength of steel. Vitreous Enamelled products can be any shape, size and colour you want.