Now it's easy to paint on ceramic, porcelain, glass, and metal with these smooth-flowing markers from Pebeo. The medium-sized round tips on Porcelaine 150 Paint Markers are perfect for writing, drawing, outlining, and highlighting, and they can be used in conjunction with Pebeo Porcelaine 150 Paints. Pebeo Porcelaine 150 Paint Markers work like other spring-loaded, fiber-tip paint markers. Simply press down on the tip firmly, and "hold" until the paint begins to flow (pump gently to speed up the process). After use, replace the marker cap securely to prevent marker dryout. When you're done painting, allow the painted surface to dry, and then bake the piece for 30 minutes at 300°F (150°C) in a conventional household oven. Since many vitreous and ceramic materials cannot withstand sudden changes in temperature, Pebeo recommends placing your painted piece in a room-temperature oven and allowing it to warm up as the oven warms up. After the piece has baked for 30 minutes at maximum temperature, turn the oven off and allow the piece to gradually cool to room temperature. Avoid the use of strong, abrasive cleaners such as steel scouring pads and sharp cutting implements such as stainless steel knives, which may leave scratches on the surface and make it more difficult to clean. Pebeo Porcelaine 150 Paint Marker colors are transparent. Opaque and semi-transparent colors are available in the Pebeo Porcelaine 150 color line. Pebeo Porcelaine 150 Paint Markers contain no toxic ingredients, and conform to ASTM D-4236. Once dried and heat-set, the durable, high-gloss finish is permanent and dishwasher-safe. These markers are not recommended for use on surfaces that come in contact with food.