You are such a neat freak. The person who dismantled it sincerely told you that as long as you keep it clean every day, the inside of the lid is also very clean. However, if you really want to remove it, you can prepare a triangular screwdriver and a slotted screwdriver, unscrew the screws inside the cup cover with the triangular screwdriver, and then pry open the upper and lower parts of the cup cover with the slotted screwdriver, so that you can remove the suction nozzle, base bracket, connector, button and other small parts one by one, and then wash them with detergent, salt or baking soda and dry them.