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Chemical scratch marks may look similar to mechanical scratch marks except that they are found in the areas of greatest stress on the glass, for example as shown in the picture above.

This is not caused by a problem with your dishwasher and service will be unable to assist with this issue

Typically there are many marks following a patterns, such as a swirl pattern.

Usually the result of:

  • Poor quality glass
  • Soft water
  • Long and high temperature cycles

Cause & Prevention


Chemical scratch marks tend to appear in the areas of the glass that are under stress or have a different composition to the bulk of the glass. These areas of weakness are attacked by the wash solution and this breaks down the lattice structure within the glass itself.

Very soft water and long, hot dishwasher cycles will only serve to increase the risk of this happening to glass, especially poor quality glassware.


Chemical scratching is irreversible and there is no treatment or way to restore the glass.


Buy good quality "dishwasher safe" glass which is less likely to exhibit areas of stress and should be more uniform in their chemical composition.

Ensure that the water is not too soft. Check with your local water authority that the water is suitable.

Do not add salt to the machine if the tap water is soft or very soft.

When possible wash glasses in low temperature, quick washes.


  How You Can Get Help With Dishwasher Problems

To offer support in helping people to determine the cause of dishwasher problems please use the dishwasher support forum.

It’s fast, free, easy and normally someone will pick up on the post that can assist you often with a few experts chipping in if needed. Just register if you don’t have an account, we don’t mail you, send you spam or any of that stuff.

Post up your question and give images if you possibly can and the guys in the forums will do the rest for you and try to identify the problem you have.

Cost you nothing, might save you some embarrassment or worse, a charge for a service visit that wasn’t needed.

  Photographs Of Damage

If you can post photographs of the damage or problem you are having this can be really helpful in allowing the dishwasher technicians to see what the problem is.

The guys have the knowledge to assist with most problems but the more information you give them, the better they can help you.

greeshma nambiar
Thanks for the tips on your site... really helpful

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