Liquid Chalk and Chalk MarkersLiquid Chalk will not wash off from rain or general watering, but it can be removed with a moist paper towel. The makeup of these chalk markers allows them to dry and crust over to maintain water/fade protection. Once the crust has been broken, the Liquid Chalk washes away. Older writing (ghosting) can be cleaned with an alcohol based hand sanitizer. Chalk pens are convenient for use with T-signs & vinyl card signs.