Scrape the chocolate substance off the surface of your khakis with the dull side of a table knife. Wipe the removed chocolate onto a paper towel and continue this process to remove as much of the stain substance as possible.
Spray the chocolate stain with a petroleum-based aerosol prewash stain remover. Allow the stain remover to remain on the chocolate stain for a few minutes.
Drizzle heavy-duty laundry detergent over the chocolate stain. Rub the detergent into the fabric and allow it to sit for 10 minutes to further loosen the stain.
Wash your khakis in warm water with laundry detergent and oxygen bleach to remove the rest of the stain.
Remove the khakis from the washing machine. Treat any remaining chocolate stain by sponging it with dry-cleaning solvent. Let the dry-cleaning solvent and the khakis dry; then wash the khakis again.