Scrape off excess deodorant using a dull knife. Remove as much deodorant residue as possible.
Pour 1/2 teaspoon of non-bleach dishwashing soap and 1 tablespoon of household ammonia into a bowl. Add 1 quart of lukewarm water to the bowl. Mix the solution.
Soak the deodorant-stained portion of the dress in the solution for an hour.
Blot the underside of the deodorant stain with a clean cloth. Remove as much deodorant as possible.
Continue soaking the deodorant-stained portion of the dress in the solution for an additional 15 minutes.
Rinse the deodorant-stained portion of the dress thoroughly with cool water.
Saturate any remaining deodorant with liquid laundry detergent. Let the stubborn smear soak for five minutes.
Launder the dress with 2 ounces of oxygen bleach. Follow the garment's care label concerning the appropriate washing cycle and water temperature.
Let the laundered dress air-dry completely.