added picture! dh said I made a horrible parenting choice because of this.
It comes right off. Took less than 5 minutes to clean both sides. Dh is still being rude about it and keeps asking me "what the f@($ is wrong with you?"
I let my 3 yo use window crayons on the slider. He said I made a bad parenting choice and this is why he cant live with me anymore.