Hello, here's some info that may give you some ideas:

https://glassdoctor.com/expert-tips/all-about-mirror-glass/bathroom-mirror-repair

This is what causes deslivering.

1) Mirrors will desilver if they are exposed to moisture from a steam bath or water splashes. Moisture results in oxidation of the silver. Also, if you live close to the ocean or sea the moisture in the air is salty, which can also cause deslivering

2) Improper cleaning such as using ammonia cleaning agents can cause mirror desilvering. The moisture from the mirror will start to create the black spots on the mirror

3) Mirror desilvering is caused by a breakdown of the silver backing of the mirror. The silver backing can break down due to age or poor initial craftsmanship.

Quality craftsmanship also play a huge role in preventing this. Some brands do not silver their mirrors properly, which will lead to these issues. You can have this repaired at some mirror repair shops if you love your cabinet and want to keep it.

And going forward, just don't be too harsh in cleaning your mirror. Using water on them to clean it is not recommended.

As for Kohler not taking any responsibility, can you take the cabinet back to the store you purchased from and the manager there can help you?

So if you shouldn't use water and you shouldn't use products like Windex, how do you clean a mirror that has things like toothpaste spots on it?

julieste - A vinegar solution or ammonia free Windex product works, or rubbing alcohol. But, the best thing one can do is buy a quality mirror that has quality craftsmanship to start with otherwise, no matter how you clean it, it will desliver over time.

Read about this in Kohler reviews on the Lowe‘s website, Kohler specifically advised against using products containing ammonia or vinegar

@Alma Carroll - Very good point, but ultimately it boils down to the quality craftsmanship on the mirror itself, which determines how to clean and what to use to clean.

Grousing online seldom works. Companies have gotten used to bad online comments.

If you want action, file a BBB complaint. Very few companies ignored these.

If that does not work, file a small claims lawsuit. Works every time. See The Warranty Game --- How to Enforce Your Product Warranty for more information.

@User - I agree that she should reach out to customer service and try to get this resolved, As for using rubbing alcohol, it is actually totally fine for cleaning mirrors. We have been cleaning with this for over 60 years. 70 percent isopropyl alcohol is an excellent cleaning agent for mirrors. It is great as a stain remover. Because isopropyl alcohol evaporates quickly, simply wet a clean cotton cloth with it and wipe. For sticky residues, you may need to rub to fully remove the mess. You can also just remove some spots or small areas of stickiness from a mirror by dabbing a cotton ball with rubbing alcohol. So, it is perfectly safe to use for cleaning a mirror. As mentioned the quality craftsmanship of a mirror plays a huge role in whether, it will desilver or not.

I was told to clean as much as possible with a dry cloth and when thats not enough to put a little alcohol on the cloth. i followed that, and mine looked great for a long time. its desilvering now around the edges but its over 20 yrs old

SIDLER® I suppose because alcohol evaporates so quickly? so if it accidentally gets on the back of the mirror, it doesn't sit there for very long?

I recently used alcohol to clean paint off of the edges of my frameless mirror, and some silver came off with it. that's where my warning came from. but I was scrubbing for a long time, right at the edge. I realize that's not a normal scenario.

Sue 430 - Good to hear the rubbing alcohol worked for you. It is also wonderful your mirror has been able to avoid desilvering now for up to 20 years.

SeattleMCM - Yes, the alcohol evaporates quickly so, it should not cause any damage unless, the mirror is a low quality manufactured mirror to begin with. Then, in that case anything can damage it or cause it to desilver. I am sorry to hear your mirror desilvered when cleaning it. Did you have to replace the mirror or what did you end up doing? I believe there are mirror repair shops that can fix this if you don't want to replace it and salvage it. Just google some and I am sure you can find someone to repair it if you are unhappy with it.

I actually needed about 12" cut off the mirror (it was too big for the space), and the cut wound up being right where the desilvering happened. solved a couple of problems for only about $35, whereas a new mirror would have been a hell of a lot more!

@User - Oh wow! I am so sorry to hear this happened. I am glad you found a solution. It is always better to try to find a way to fix it vs. replace it as the latter is more costly. I am glad you found a solution.

Yes! this exact thing happend to both of my vedera kohler medicine cabibets and i use water and a microfiber cloth to clean them. Kohler will not replace ours either. We are not impressed with Kohler products, unfortunately

I had this happen to all of our Kohler vedera medicine cabinets (4 in total) after only a few years. These were more expensive than the mirrors we put in another restroom, which did not have this problem. I agree these are crap medicine cabinets and not worth the price. Kohler is still selling these medicine cabinets knowing they are defective. I recommend going with a different brand.