These markers can be written on a variety of surfaces such as: plastic, metal, wood, glass, plaster, canvas, etc. The pigment can be peeled off from non-porous surfaces such as glass, but will permanently adhere to porous surfaces such as wood and paper. Water-based pigment inks are non-toxic, fast-lighting and waterproof. The ink will not bleed through paper (unlike alcohol-based markers) and is great for brightly colored signs and craft work.