How do I get melted chocolate stains out of my dress shirts?

I left 2 or 3 Hershey's kisses in one my dress shirts. I washed and dried them with 4 other dress shirts and, yes, you guessed it, chocolate all over every one of them. I washed them again and the chocolate came out, however there are these dark spots where the chocolate once was. How do I get these dark spots out? One dress shirt is cotton, one sateen, the other a mix of cotton and something else. Please help!