Grab a cotton ball and soak it with acetone-based nail polish remover (you probably already have it in your makeup cabinet.)
Put the cotton ball on the affected parts of your scalp and let it completely soak through the glue. This should only take a few minutes.
Use an acetone-dipped cotton swab to reach those places you can't get to with the cotton ball.
Comb out the nasty nail glue chunks loosened by the acetone. A wide-toothed comb is best, but you can also use a fine-toothed comb -- just be sure you don't snag your hair on the glue chunks. Ouch!
Peel off any remaining nail glue left on the scalp.
Repeat the steps until you get all of the nastiness out of your hair.
Wash, condition and style your hair as normal. Be sure to spend a little extra time on the shampoo lather to get the acetone out of your hair.
Acetone can really dry out your delicate skin, so apply leave-in conditioner directly to your scalp to moisturize the skin touched by acetone.
Don't you dare cut nail glue out of your hair! Get your rear to a professional stylist if you get a lot of nail glue in your hair. Your stylist is better equipped to get the glue out of your hair.