Crayons

A few questions about crayons:

It's okay for a kid to injest a little crayon every once in a while, right?

How do you get crayon off clothes?

How did people get crayon off the walls without Mr. Clean's Magic Eraser? Seriously. (And how do the kids write on the walls without you noticing? I mean, Ezra hasn't had crayons in days and all of a sudden I notice outrageous orange, radical red, and purple pizzazz marks all over my entryway.)