Glaze liner pens sour grapes purple glaze in a pen perfect if you want to do some fine detailed work and ideal for those who want to try something other than a brush shake well before use and first test on a piece of paper this will remove any air bubbles and allow a consistent flow hold the tip in contact with the ceramic at an angle and apply using a very slow handwriting motion this glaze is so versatile that it can be used as an under or over glaze lead free and non toxic so safe f