Moldex Review

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The word killer always puts me on the defensive. I immediately feel like this product is going to claim to kill mold on contact without the need to actually remove the mold as well.

Moldex Mold Killer is an EPA registered 3-in-1 cleaner designed to kill, clean and inhibit the growth of mold and mildew.

It destroys and neutralizes mold, mildew and their odors at their source. It is not a masking agent or general purpose stain remover. It’s bleach-free, phosphate free, non-abrasive disinfectant mold killer.

Bottles of Moldex Mold Killer

When I was researching Moldex I found an interesting blurb on the Rust-Oleum website (the parent company of Moldex) about Mold Killers vs. Mold Removers. Here are the highlights:

 Experts say you need a two-part strategy for mold – kill it and clean it.

 Killing mold and mildew growth requires an EPA registered biocide,’ says Brian Joyce, brand manager at Moldex.

Moldex Mold killer is a biocide that disrupts the life cycle of mold and protects against new growth. Just as a weed killer is designed to kill weeds, once the plant has died, you need to remove the dead biological growth to finish the job. In order to ‘lift’ or ‘remove’ what’s beneath the surface (mold stain) after the organism has died, you need a powerful cleaner.

Removing the Stain

Most stains are removed by dissolving them, but the effectiveness of the cleaner depends on two factors: the cause of the stain and the material that has been stained. 

‘Different cleaners dissolve different stains.  Moldex Instant Stain Remover is a bleach-based product that removes difficult mold and mildew stains on surfaces that are bleach-friendly,’ Joyce explains. 

So you really need both a killer and remover?

Yes. Stain removers lack the ability to effectively kill the living organism that causes mold and mildew. 

‘Do your homework,’ Joyce says. ‘Ask the representative at your local hardware store what they recommend.  They should know the difference between a mold killer and a mold stain remover.”

Not only is the bulk of this information incorrect but the advice to speak with someone at a hardware store about mold is reckless. Typically they don’t know much about mold.

Moving on…

Active Ingredients

  • Dimethyl benzyl ammonium chloride – 0.3%

Pros of Moldex

  • Works against 99.9% of all household germs, bacteria and viruses
  • Gentle on all surfaces
  • Works well for sewage backups and gray water clean up
  • Noncorrosive
  • Ready to use – no dilution needed
  • No rinsing
  • No rinse formula

Cons of Moldex

  • Only safe to use on washable surfaces
  • Has a Prop 65 Warning in California. This means that it can expose you to chemicals which is known to the State of California to cause cancer and birth defects or other reproductive harm. 
Moldex Mold Killer Products

Toxic or Non-Toxic

Not completely non-toxic as Moldex does have a teeeeeeeny, and I mean teeeeeeeny amount of the dreaded dimethyl benzyl ammonium chloride. I have yet to meet a product with this small amount in it. So I would say that Moldex Mold Killer is safe as long as you don’t swallow it.

Final Verdict

I’m not confident in Moldex and would not suggest anyone rely on this for their mold problem. But if you would like to purchase it, you can find Moldex Mold Killer here.

Curious about the other mold removal products I have reviewed? Come check them all out here so you can choose the right product for your mold situation.

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  1. david murray says:


    I work in a 160 yr. old church that had a mold problem on the wainscoting, below the chair rail. I followed the directions for mixing and application, but when I went to flush the walls with water, the Moldex product had dried and left a mess of white water spots and dribbles behind. I’ve tried EVERYTHING to reactivate the stains, but to no avail. Spoken with the company and, of course, there’s nothing they can do. The label makes no mention about not allowing the product to dry on the walls. Can you suggest anything? I would be most grateful for any suggestions you night offer. Thank you kindly, David

    1. Hi David! I had to ask a couple of people if they had any ideas. I couldn’t think of anything. My contractor friend said to mix 2 parts vinegar with one part water. Add three drops of lemon essential oil. Use a new microfiber cloth. Dip it into the solution making sure to wring out excess water. Using elbow grease, wipe down a small section of the wainscoting. Immediately dry the section with a different microfiber cloth. He said you might have to repeat each section once more if the staining is really bad. Let me know how that works!

  2. Lila Holdenried says:

    If you don’t recommend.. what do you recommend for the homeowner to use? We have issues with vaulted ceiling bathrooms and low air circulation in those rooms.