Is there a trick to get chocolate out of clothes?

Let it set and scrape off what you can with a blunt knife - ten minutes in the fridge makes that easier. Then run cold water through it from the back, so you push it out the way it went in. Rub in a bit of liquid detergent, leave it fifteen minutes, wash as normal. Keep it out of the dryer until it's completely gone, heat bakes in whatever's left.