Abstract: A leakproof disposable container lid is made out of the same plastic material that an ordinary container lid is made of. The present invention adds a simple slot to the lip of the lid. A portion of the outer edge is raised forming a slot. A hole is made in this raised portion. A curved piece of lid material with a matching hole slides through the slot. This inexpensive lid prevents spilling while in transit, especially in moving vehicles. The improvement can increase the popularity of take-out beverage items at fast food restaurants reducing spills inside vehicles and at home.