With Chalk-O-Rama Chalk Crayons, You Can Show Off Your Creative Expression On Nearly Any Surface. You Can Write With Chalk On Glass, Wood And A White Board? Yep, Yep And Yep. Chalk-O-Rama Is The Go-To Chalk Set For Colouring Your World. Chalk-O-Rama Chalk Crayons Write On Both Porous And Non-Porous Surfaces. Try Them On Glass, Windows And Mirrors. They’Ll Work On Cardboard, Wood, Whiteboards And No Doubt These Chalk Sticks Will Write On Chalkboards. And Let’S Not Leave Paper Out Of The Mix Because Chalk-O-Ramas Will Write On That Too; Including Black Paper. Chalk-O-Ramas Will Wash Off Easily On Non-Porous Surfaces Like Glass And Whiteboards But Are A Bit More Permanent On Porous Surfaces. There’S No More Dusty Hands With These Chalk Crayons Either Because Chalk-O-Ramas Are Encased In A Plastic Barrel; Just Give It A Twist Just Like Lipstick And You’Re On Your Way To Colourful Creativity.