Magic erasers, baking soda? Any tips. You leave the kids unattended for thirty seconds and the hallway has turned into a damn Picasso.
Your classic go-tos are: nail polish remover and hairspray (I’d go with the former first). If you wanted a product then, if in doubt, I always reach for Dr Beckmann’s and the their Stain Devils range has a pen and ink remover that also works crayons (although that makes it sound suspiciously generalised) - with young kids in the house I’d have that and the trust carpet stainer remover to hand (well, I keep the latter in easy reach generally).
Might just have to repaint at that point.
Deodorant worked for me in the past, but it was quite a while ago, and in a nightclub, so there’s a chance that it might not work with decent paint.