Gently scrape off excess chocolate. Blot the stain with an ammonia solution. Next, without rinsing, blot the stain with liquid laundry detergent or a pre-treat and flush with cool water. Blot the remaining stain with a strong white vinegar solution, and launder with cool water, as usual. Before placing garment in dryer, inspect. If a stain remains, blot with a cleaning fluid, flush with cool water and re-launder with cool water, as usual.