Multicraft Glass Paint Brush Marker are designed for glass and glazed ceramics. They can also be used on porcelain and metal. Great for personalization, outlining or drawing. Bake in the oven for a durable, dishwasher-safe finish. Permanent Purple- Pen has a long flexible nylon nib to allow you to create super fine to thick bold lines just by adding pressure. Bake at 160 degrees for 30 minutes. Avoid sharp objects as it may scratch paint.