Mold Control on a Budget


Least-toxic cleaning and encapsulation products can be effective and healthier. You no longer have to replace mold contaminants with chemical pesticides (mildewcides).

Most homeowners  would prefer to go a least toxic route, i.e., a healthier route for cleaning up mold and mold removal. But homeowners want to make sure that mold isn't going to grow back a couple of weeks after the mold removal job is done.

In close to 20 years of environmental inspecting, I have had the opportunity to see many products -- both conventional cleaning and encapsulant (sealant) products from the mold industry, as well as "green" products.

Because I work with a microscope on-site, I have sometimes been able to see products that fail to kill mold, fail to prevent future mold growth, or perhaps both killed mold and prevented future mold growth but were themselves toxic to homes and families.

Here are some of my observations:

  • It can be very hard to discover if the conventional mold removal product contains one or more chemical pesticides. Manufacturers are not required to list chemical pesticides (also known as "mildewcides") on their information sheets, known as the MSDS sheet (Material Safety Data Sheet). If you ask for a copy of the MSDS, it will tell you some information about some of the ingredients and possible side-effects, but it won't tell you ingredients considered "trade secrets," nor will it typically tell you about any pesticides.
  • If you have the product's EPA registration number, you know there are chemical pesticides in the product and you can track down which ones.
  • Some of the most popular products contain one or more pesticides. In some states, the mold remediator has to have a pest-control operator's license in order to legally apply the mold remediation product.
  • Least-toxic products sound better, but I have sound found some that aren't effective for very long. You don't want to spend money on mold remediation, only to find that mold grows back shortly afterwards.
    Some least-toxic products can be fine for cleaning, but not for long-term sealing of the surface.
    Least-toxic products include herbal, enzyme, essential oils, and spice products, as well as other least-toxic mixes. Some green products contain mildewcides.

You ask, "What least-toxic products do work and last a long time?"

Borax - my favorite product for cleaning

Borax is a common cleaning product, available in the laundry aisle of a supermarket for around three dollars a box. Borax is a white mineral powder. When mixed with water and used as a cleaning solution, it has an abrasive action that easily cleans mold off a surface, even a semi-porous surface.
I have seen before-and-after samples under the microscope where Borax was used to clean off significant Aspergillus growth from OSB (oriented strand board), which is supposedly not easy to clean. Just a firm wipe-off was effective. Scrubbing was not needed.

Point of Information: Although the word "green" commonly refers to "least-toxic," please be advised that "green" is not always "least-toxic." Recycled goods are generally considered "green," yet if the original goods were toxic, the recycled version would be toxic, too, just recycled toxic. I would have no idea if "green" cleaning products are also "least-toxic."

I don't use the words "non-toxic," because even though a product is effective and doesn't off-gas volatile chemicals, you still might not want to drink it - such as lime or Borax.

How to use Borax in mold removal:

  • HEPA vacuum loose mold.
  • Mix 1 cup of Borax per gallon of water.
  • Use a cloth, spong, or scrub brush to clean a small area (1-2 square feet). Do not over-wet, because the more moisture, the more mold growth. Follow the cleaning with an immediate wiping semi-dry with a clean, dry cloth.
  • Allow to thoroughly dry before applying a sealant (encapsulant).

Question: isn't chlorinated bleach the best thing for killing mold?

Answer: I have found chlorinated bleach only a mediocre product for cleaning up mold. Besides, you don't need to kill the mold. Just get rid of it. Borax works much better -- and I've seen this multiple times under the microscope. I think the folk who tell you to use chlorinated bleach must not work with a microscope or they'd know better.
At one house under construction, there was visible mold on drywall. A worker sprayed 100% bleach (not safe!) on the mold. Some hours later, I arrived for testing, and the sprayed mold was still there.

Caliwel - my favorite product for encapsulation

  • After the surface is clean, it should be sealed. Caliwel is an effective least-toxic product that encapsulates cleaned surfaces. Caliwel is lime-based and does not off-gas chemical pesticides as many conventional mold remediation products do. For more information about Caliwel, go to If you want to use Caliwel and are working with a contractor, your contractor can order directly for a contractor's discount. Call 1-212-317-0100. (I have no financial interest in Caliwel.)
  • If you are on a really tight budget, you might try working with whitewash, which is basically lime plus water. Caliwel is whitewash with a binder, to make its effectiveness last longer. I have no experience in working with whitewash and suggest you do an Internet search for a recipe, i.e., "whitewash + recipe." Whitewash is an old-fashioned remedy to protect vulnerable surfaces. Every spring, countless people around the world whitewash their homes (and even the bottoms of trees) to protect them from mold and insects.

Question: I've seen other products, both conventional and green, at a local home supply store. What you think about them?

Answer: With conventional products, you run the risk of offgassing from toxic ingredients, and with green products, you don't know how long their effectiveness will last or whether they really are least-toxic.
Borax and Caliwel/whitewash are least-toxic products with proven effectiveness, so I don't see a need to look further. In fact, the Alistagen folks say that you can use Caliwel over a moderate amount mold (after HEPA vacuuming), that it kills mold on contact and allows you to skip the cleaning phase. That would save a lot of elbow grease. Be apprised, though, that all the national guidelines say you should start with a clean surface. You'll have to find your own comfort level here.

I've seen Caliwel kill mold on contact. At one house under construction, rain got into a small, inaccessible crevice-like area. The builder would have had to take down a good portion of the structure to access the mold, so as a compromise, the area was sprayed thoroughly with Caliwel. (National guidelines allow for compromises when necessary.)

A couple of hours later, I arrived with my microscope. Samples revealed both Caliwel and mold spores. What I saw under the microscope were Stachybotrys spores that were dessicated, misshapen, and rupturing. It was quite impressive to see.

top of page


Tell a Friend

EnviroHealth Consulting, Inc., 1-888-735-9649

Mold and other environmental inspections available in

  Connecticut - Maryland - New Jersey - New York - Pennsylvania - Virginia - Washington DC and other areas

Updated 9-2011