IRWIN Tools STRAIT-LINE Dust-Off Marking Chalk, 6-ounce (4935426) This temporary chalk can be used to mark interior walls and trim, then wiped away cleanly. Flip-cap keeps the chalk in the bottle where you want it and stops it from spilling out in areas that you don't. Flip-top cap also seals the chalk in an airtight chamber, keeping out moisture and reducing the risk of clumping. Light violet color is easy to see, but wipes off easily when you're finished working.