Borax is a mineral. It is in the form of flakes or powder.

Be careful. Borax may be irritating. Its pH is close to 9.

Warning: Contains sodium tetraborate decahydrate. Avoid contact with eyes. Do not ingest. 
In case of accidental ingestion: Rinse mouth and drink several glasses of milk or water. Call a doctor immediately. 
In case of accidental eye contact: Rinse with water for 15 minutes. If irritation persists, seek medical advice immediately.

History

Borax was discovered in 1875 in the Valley of Death in California, United States. It is usually found in old dried lakes where the water has evaporated.

Before the 2000s, borax was a common household product. It was a popular and effective cleaning product. It was used to disinfect, whiten and fight moulds. It could also be used to get rid of ants (used as a low-toxicity pesticide).

Many DIY (“home-made” cleaning recipes included borax as an environmentally friendly option for petroleum-based ingredients in conventional cleaning products.

Does Borax kill mold?

Most, but not all types of mould, prefer an environment with a pH between 3 and 7, which is more on acid (a pH of 7 is considered neutral). Some molds even like to live in a pH-like environment below 3.

Borax is fairly alkaline with a pH around 9.3?Applying the borax to mold this creates an environment that is not suitable for the additional growth of mould. In many cases, borax kills mold spores by increasing pH levels and making it their inhospitable environment.

How to remove moulds with borax

You will need:

• Borax
• Water
• One 5 litre container
• Glass spray bottle
• Brush for rubbing, old rags or sponge

Method 1 – spraying of bullden moulds

1. Place 1 cup of borax in the 5 litre container.
2. Fill the container with hot water, put the lid and shake it well. This helps to dissolve the borax more completely and more quickly.
3. Pour the solution into the spray bottle.
4. Spray the affected area. Take care not to use too much on porous material, such as unfinished wood or drywalls. These materials absorb water, which will feed the mould by keeping it moist.
5. Rub the area with a brush, cloth or sponge until the mold is removed.
6. Wipe the clean area and dry the area. You can iron a slight mist of borax spray over the mould.
7. You don't need to rinse afterwards. Borax will usually prevent mould from coming back as long as you have touched on the source of the mould, including if there are leaks or water infiltration problems.

Method 2 – Borax paste

Often referred to as "borax paint", it is a method used to kill mold on the wood, not to remove mould, so to speak. It is not recommended to leave mould wood in place and then apply a mold destruction product to the wood. It is better to remove any moldy material and start in the fresh state.

1. In a 2-quarters saucepan, mix 1/2 cup of borax and 2-quarters of boiling water.
2. Shake well until most of the borax is dissolved. A little borax at the bottom of the saucepan is ok.
3. Using a brush or cloth, cover each part of the mould with the borax paint.
4. Allow to dry.
5. You can paint the wood over the mould paint or paint before treatment if you want.