Place the garment on a flat surface with the spaghetti sauce stain facing up. Scoop any sauce substance off the garment with a spoon to prevent it from spreading further into the fabric.
Cover the spaghetti sauce stain with baby powder to absorb the grease. Allow the baby powder to remain on the garment for 20 to 30 minutes, then brush it off.
Put the stained portion of the garment into a bucket. Pour undiluted white vinegar into the bucket to completely cover the stain. Soak the garment for 10 minutes to loosen the rest of the tomato-based stain.
Wash the garment with laundry detergent and all-fabric bleach. Before drying it, check the garment to make sure all of the stain is gone. If any of the stain remains, rub laundry detergent onto it and soak the garment in warm water for 30 minutes before laundering it again.