Submerge the chrome cups into a sink of warm water.
Add 3 tablespoons of dish soap to the water. Agitate the water with your hands to create a lather.
Scrub the cups with cotton cloths thoroughly on the inside and outside of the cups. Rinse under running water and dry with a clean cloth.
Measure a foot-long sheet of aluminum foil.
Pour 1/2 a cup of cola over the aluminum foil.
Wipe the cups with the saturated aluminum foil in a circular motion to remove rust stains. Wash the cup and dry it with a clean cloth afterwards.