Securit Liquid chalk markers allow users to write on chalkboards, glass, metal, plastic or any other non-porous material. Once the chalk is dry it is resistant to smudging and even light rain. To write a new message simply use a wet cloth to wipe the surface clean. Chalk marker Stencil sets are available for the artistically challenged and we recommend for the Securit cleaner to be used on the writing surface at least once a year to help protect the product. Liquid chalk is by far the easiest and trendiest way to communicate to customers; hand written messages are more personal and organic. The wipe clean solution provides businesses with a fast, low cost advertising canvas. This markers have an edged nib.