Killing and removing mold a greener way

First published June 2008, updated April 2010

As I’ve mentioned in a few other articles, I used to be the cleaning chemical king. My cleaning cupboard was somewhat like a trophy shelf with sprays for this and liquids for that. Not only did I have a range that would put most supermarkets to shame, but I used lots and lots and lots of them – it was a case of “if a little works, more will work better”.

Cleaning chemicals can be nasty stuff both to us and to the environment generally.

I remember back in the days when I was known to have a drink or two (hundred), I decided to go on cleaning frenzy in the bathroom with mold killer – not that it really needed it, but:

a) I saw it as being solid preventative action
b) I was blotto

I don’t know of too many drunks who clean when inebriated, but being mildly eccentric when even sober, I guess it just seemed like a good idea at the time. To cut a long story short, friends found me passed out in the shut bathroom, still clutching the bottle. They would have had to pry it from my cold, dead hands – luckily, that scenario didn’t eventuate.

I was sick for days afterwards, long after the hangover subsided. My throat was sore, I had the continuous sniffles and my eyes were bloodshot a result of my mad mold killing mission.

The “old” me is the reason why manufacturers put directions on bottles that make you think “what sort of stupid fool would use this stuff in a room with poor ventilation anyway”. :)

Commercial mold killers are usually made with Sodium Hypochlorite (bleach) and Sodium Hydroxide. They are highly corrosive. Sodium hypochlorite is very toxic to fish but is easily diluted. The problem is chlorine in bleach can attach itself in an aquatic environment to organic matter and form organochlorines, highly toxic substances that can persist in the environment for a very long time.

Green mold killer and cleaner options

My drinking days may be well behind me, but I’m still on somewhat of a 12 step program when it comes to cleaning fluids, lapsing from time to time but overall doing much better than I was.

Something often leads me to fall off the wagon is mold. Just ordinary mold that builds up in the shower. Here are some green alternatives I’ve tried or seen recommended by others that work to a varying degree depending on the situation.


A teaspoon of environmentally gentle dishwashing liquid and a teaspoon of borax mixed with one quart warm water; pour into a spray bottle, soak the affected area for as long as possible; rinse and air dry. More handy borax tips

Eucalyptus oil

One tablespoon of eucalyptus oil, one tablespoon of methylated spirits and two cups of water mixed together and placed in a spray bottle; apply and leave to dry. More eucalyptus oil tips.

Grapefruit (or citrus) seed extract

Mix 20 drops of grapefruit seed extract with 2 cups of water; place in a spray bottle and apply. Leave to dry


1 part vinegar to 4 parts water mix, again sprayed on and left to dry. More vinegar tips.

Baking soda

Pour 1 part vinegar and 1 part warm water into a bowl, then add 2 parts baking soda to make a thick paste. Apply and leave to dry, then scrub off. Repeat if the mold is particularly stubborn. More baking soda tips.

Tea tree oil

1 teaspoon of tea tree oil mixed with 2 cups of water. Place in spray bottle and mix well. Again, don’t rinse

Most of the above are safe to use on bathroom tiles and ground; exercise caution with other materials. Regardless, spot test first.

If green alternatives fail

Hopefully one of the above tips will help you deal with your mold situation in a more environmentally friendly way, but I’ve found some mold problems will be so bad or ingrained you’ll need to resort to some of the more heavy duty stuff.

I’ve come across a couple of situations where even tea tree oil, the big daddy (and most expensive) ingredient of earth friendly mold killers, won’t shift it. In these cases, I’ve gone back to chlorine based mold killers; but approaching it a different way.

Firstly, I stay sober. This is incredibly important :)

In the case of the shower, I create a dam around the affected area with rags or old towels in order that none of the runoff gets in the drain. Then, instead of spraying it around like there’s no tomorrow as I used to, I get the nozzle as close as I can to the affected area and pull the trigger slowly, doing the best I can just to hit the affected area and nothing else.

I wipe off any runs and then after leaving overnight, I hit it with tea tree oil and allow that to dry off naturally. The adding of tea tree oil after the mold is visibly gone does certainly seem to prevent mold from reoccurring so quickly. That ounce of green prevention is certainly better than the pound of corrosive cure.

If you have some earth friendly tips for removing mold, please add them below!