Cleaning an Old Easel Board

I check out some of the other email postings. I recently received an easel board from another family member - they had a lot of writing with grease markers on it, and they don't know how long it was on there.

So we, my other half and I, tried rubbing alcohol, then nail polish remover, and then hand sanitizer gel. None of them worked. Then we tried Permatex Fast Orange - hand cleaner. This works great with a little extra scrubbing.