Plastic is a material that is particularly prone to absorbing odors. If you use plastic cups to drink particularly strong smelling beverages, the smell may linger in the plastic long after you clean it. Even long soaks in soap and hot water may not be enough to completely remove the odor from the cups. Products with strong deodorizing properties are essential for making plastic cups revert back to their previous states.
Pour 3 cups of warm water into a bucket or large bowl. Add 1 cup of baking soda and stir the mixture until the baking soda is evenly distributed into the water.
Place your plastic cups into the bucket or large bowl. Let the plastic cups sit in the baking soda solution for at least eight hours.
Take the plastic cups out of the baking soda solution. Rinse them with warm water to remove any lingering baking soda. Dry the cups thoroughly and smell them to determine if any odor remains.
Moisten a paper towel with white vinegar if the plastic cups still smell. Rub the insides of the plastic cups with the vinegar-soaked paper towel to help further remove any odor.
Wash the plastic cups with liquid dish detergent and warm water to wash away the vinegar. Rinse the cups with warm water and dry them thoroughly.