sometimes were asked by customers wire Inc word wiped clean from their boards liquid chalk is easy to remove but it's important you use it on the correct surface all liquid chalk products are designed to be used on smooth non-porous surfaces that means that they don't let liquid absorb into them this leads to staining so when using a liquid chalk marker first thing you need to check is that the material of the object you're writing on is non-porous this can include many products such as glass ceramics or metal be careful though some products may seem non-porous but they are many chalkboards are merely wood painted with chalkboard paint these are porous some surfaces may also be too rough watch as we demonstrate the same pen on three different surfaces for glass board a non-porous chalk board and the porous chalk board when you buy a chalkboard please look for chalkboards which state they are made for use with liquid chalk now watch when we try to erase on the different surfaces we'll give each surface a quick wipe with a wet cloth the glass board and the non-porous chalkboard wiped clean very easily the poorest board however leaves ghosting this is because liquid chalk is designed to be used with non-porous surfaces don't despair however if your board is porous and you're having difficulties cleaning off the liquid chalk we have some suggestions to help you watch our next video to find out more you