To clean spilled drinks in a car, follow these steps: Act quickly to prevent the spill from spreading and soaking into the upholstery or carpet. Blot the spill gently with a clean cloth or paper towel to absorb as much liquid as possible. Mix a mild detergent or upholstery cleaner with water, and apply it to the stained area. Use a soft brush or sponge to gently scrub the stain, working from the outside toward the center to avoid spreading it further. Rinse the area with clean water and blot it dry with a towel. If the spill has seeped into the carpet, you may need to use a carpet cleaner or take the car to a professional detailer for deeper cleaning.