Carpenter & Masonary Crayons
Carpenter's crayons are great for labeling materials (lumber, wall messages, etc). They mark on any rough or wet surface. They are preferred over paint-pens for items where you want the markings to eventually 'go away'. Crayon markings don't wash off or fade from sunlight. They just sort-off wear off in a few weeks. Use a carpenter's pencil for measurement markings. Use a carpenter's crayon for labeling, and other message-type markings.