Soap Scum occurs when soap bonds with hard water particles. It can create a cloudy or smudged appearance in your drinking glasses. A water softening system can be installed in your home to prevent soap scum. Some dishwashers have a special soap scum prevention cycle, but it may not always work if you use too much detergent. Soap scum is more of an eyesore than a danger, so a simple cleaning to remove the dull appearance is all that is necessary.
Apply a small amount of white vinegar to a clean cloth.
Rub away the soap scum film or spots on the glasses.
Rinse the vinegar from the glasses.
Dry the glasses with a clean dry cloth immediately after rinsing to prevent any hard water deposits from adhering to the glass.