Hands Are Not For Hitting and Marshall Is NOT For The Library

I did the UNTHINKABLE today. I took Marshall to the library. Yes, I know...I should have known better! He did OK until it was time to check out. Then he ran around and I couldn't catch him. He grabbed a book off the shelf and told me "When I am big, I will read this." I told him he's not big enough yet. He said I could read it and wanted me to check it out. I put it to the side and tried to hurry and check out. The next thing I know, a man came around the corner holding a book and pointing at Marshall saying "He threw this in the trash can." AAAAAAAAAAAAAAAAAAAAAAAHHHHHHHHHHHHHHHHHHHHHHHHH!!!! This is AFTER this darling child of mine got a green dry erase marker while I was getting dressed and colored on the floor and walls of the kitchen. So, does anyone have ideas about how to get dry erase marker off the wall without ruining the paint? It wouldn't be so big a deal if we weren't renting!
On a good note, we got 2 really great books about anger and hitting. One is called Hands Are Not For Hitting. We haven't read the whole book yet because it's hard to get Marshall to sit still. Plus, we like to talk about the book and practice the things it's teaching. The book shows drawings of kids who have hit other kids. It talks about how it feels to get hit and how we don't like it. It talks about the reasons why we hit. I think it holds great potential for helping Marshall learn to stop hitting. I can talk to him until I'm blue in the face and it does no good but if he reads it in a book, it has a chance to get through to him.
We also read "When Sophie Gets Angry, Really Really Angry". That one is about a little girl who gets angry at her sister and mother. The more angry she gets, the more red is colored around her. As she calms down, she goes back to being outlined in yellow/brown. It's a good book for him. He really likes it and asked me to read it to him 3 times today. When I find a book that interests him, I can get him to sit with me for a while. He always says the same thing at the same spot in the book. He loves to read books he has already heard because he hates change.