How Do I Clean This?

The scare about the sponges burning kids has never been backed up by real evidence. Check out:
http://www.mayoclinic.com/health/chemical-burns/AN01706
You can't believe everything you read on the internet without checking it out first. A good site to check out whether something is a hoax is:
http://hoaxbusters.ciac.org/
As for the marker, sanding it out might work if it didn't penetrate too deeply. Last resort - work the design into a larger design and decorate the whole thing!

Magic eraser sponges may do the trick, but keep in mind it will give a toddlers skin a nasty chemical burn if they get ahold of it... You can go to home depot and the paint department ask the counter clerk for a product that covers or removes paint and marker.. I know they have it because I purchased it from there I forgot the name though.
Here is a link with some tips too.http://www.mrscleannw.com/tips/remove-marker-stains.html
http://www.associatedcontent.com/article/484015/ways_to_r...

Hi M.,
i find that the mr clean easer sponges are amazing i use them to clean everything in my house markers crayons etc they work wonders

You can try Bon Ami. It's gentle and shouldn't damage the wood. (plus it's not a heavy chemical like the Magic Eraser) It really helped us get the red sharpie off the counters, sinks, walls, tables....that our own little Picasso created.

Good luck!

rubbing alcohol and a sponge may do the trick. also, i've seen them do paint tricks with denatured alcohol. that may work, too. i'd google 'permanent marker removal'

I'm sure your gonna love my response. There really is nothing you can do. I has sunken into the wood. You can try to sand it out but there is no way of knowing how deep it goes. As for the painting thing. No paint will cover permanet marker. My sister has a friend who is a contractor and some clients went through their new (being built) house with a bright red sharpie circling all the mistakes. Not to bright because he told them that all that dry wall needed to be removed and replaced because they were idiots. So the only thing you can really try is sanding. I don't think that the Mister Clean sponges will work on untreated wood.