My glasses have a rainbow appearance after they have been washed.
Do not attempt service or replace parts of the appliance unless referred to in the owner's manual. Follow all safety precautions provided in the owner's manual.
Over time, a combination of soft water, too much detergent and heat can cause permanent damage called etching on some types of glassware. The beginning stages may be identified by an iridescent look. Shades of blue, purple, brown or pink may be seen when the glass is held at an angle to the light. In advanced stages, the surface of the glassware appears frosted or cloudy. To test for residue, soak a glass in white vinegar for 15 minutes then rinse with water. Any residue or discoloration should be removed, unless etching has occurred.  
 
To reduce etching, adjust the amount of detergent based on the water hardness, lower the water temperature and use the Air Dry option.