J.L.
I can't tell you how many times my daughter did this!!! I tried everything to get it out. Dawn dish soap did not work. This will sound strange, but the only thing I found that worked was that "Gojo" hand cleanser stuff that mechanics use to get grease off their hands. It is a little hard on the hair, but it works. I would follow it up with a good conditioner and let it soak in for a little while. I'm sorry to hear that my daughter isn't the only child to do this! Hopefully she'll only do it once ;)
J.