Remove as much of the excess barbecue sauce as possible from the fabric.
Run cold water through the back of the stain as quickly as possible. This will force the stain back out through the fabric.
Rub a liquid detergent into the stained portion of the fabric. Work it in gently.
If the garment is white, or you have tested it for colorfastness, apply a mild bleaching agent like hydrogen peroxide or white vinegar with a sponge. You can also use lemon juice on white fabrics. Rinse well.
Repeat with detergent followed by mild bleaching agent until the stain no longer appears.
Apply a stain remover stick, gel, or spray and allow it to sit for at least 5 minutes.
Launder with detergent. Before drying double check the stain.
If the stain remains, rub detergent into the stain and soak in warm water for 30 minutes. Rinse well.
If the stain remains, apply stain remover stick, gel, or spray and launder according to directions.