Step 10 = Stop black mould with Tea Tree oil.
Black mould is really bad news for household health. Breathing in black mould spores can worsen the state of delicate lungs (e.g. in babies, the elderly and asthmatics) and it also exacerbates all kinds of allergies. Continued exposure to black mould has been linked to depression, anxiety, headaches, skin complaints and joint pain. Eek!
If you do have black mould in the house then Google what to do. If it is a large area affected and / or there are lots of loose spores, then follow the online advice of getting a professional in (they will have thick gloves, coveralls and an industry-grade face mask).
If it is just a small, newly colonised area then still bear in mind that black mould is tricky to deal with - for instance, if you wipe it over with bleach and then fail to wipe the bleach fully away, then the remaining surviving mould spores will use the traces of the bleach chemicals (once the bleach has deactivated over time) as a substrate (ie food source) to grow on! Black mould is clever and resourceful. We need to be cleverer and more resourceful than the mould...
First, open the windows wide! Next, wearing gloves (and preferably eye protection - swimming goggles or wrap around sunglasses are better than nothing) wipe over the windowsill / shower cubicle / window frame / wall / wherever the mould is, with bleach spray, sprayed onto a cloth.
I favour 'Dettol Mould and Mildrew Remover' (it comes in a bright green spray bottle) as it doesn't catch the back of the throat like other bleach sprays do. In fact it smells reassuringly like a clean swimming pool. But for stubborn black mould stains you'll need to use HG Mould Remover Spray or (the miracle-working product from my years as a domestic cleaner) Kilrock paint-on treatment. It seems to now be sold in a white bottle, but the amazing one I used was in a black bottle with a brush-top, I hope the new version is as good!
I'll repeat the OPEN THE WINDOW instruction. Plus make sure no pets or children (or unsuspecting adults) are around and leave the bleach to work for 5 minutes (or however long the back of the bottle states).
Obviously the bleach will probably dis-colour the surface you are wiping, but as it is already covered in black mould it probably isn't an area that is precious to you. (If it is a surface you care about, then first test the bleach spray on an inconspicuous area.)
After the 5 minutes, wipe the black mould and bleach away with warm water using paper loo roll (or you could use disposable kitchen roll if you have it, we don't as ours is bamboo reusable kitchen roll). Repeat the warm-water rinsing three times, to be sure that the area is as clean as possible. Don't use hot, steaming water as you don't want a steam cloud of bleach fumes in your face!
Dry the area thoroughly with something disposable - loo roll / kitchen roll. You do not want to be introducing black mould spores into your washing machine via a cloth or towel!
Then comes the secret weapon! Tea tree oil is the arch enemy of black mould. Black mould really doesn't like tea tree oil. Hurrah!
For easy application, buy an atomiser spray cap from Amazon (with an 18mm neck) to fit 100ml glass bottles of Tea Tree oil from Amazon, sold by Naissance (this brand of tea tree oil comes in plastic-free delivery packaging, so is my current favourite - the brand in the picture above is also good, but is pricier). Spraying a fine mist is much less wasteful than 'sloshing' on the tea tree oil, so buying an atomiser spray top is worth it. If you want to refill the small bottles, then 'Mystic Moments' on Amazon sells huge 500ml metal bottles of tea tree oil (admittedly with a plastic screw top) which will keep you going for a good long while. This large bottle is sent out packaged within a papery-card version of bubble wrap happily.
So, spray / shake a few drops of tea tree oil over the affected area (windowsill / window frame / wall / wherever) and rub it over the area using kitchen roll (bamboo kitchen roll is a great re-usable alternative). Again, the oil may stain the surface so do a test-patch first if that thought bothers you.
An additional bonus of this procedure is that your house will then smell like a health spa, thanks to the essential-oil aroma!
Obviously, the tea tree oil treatment won't work in a regularly used shower / bath area as it will be washed off - but applying tea tree oil is perfect for places which are hard to bleach and rinse weekly.
Repeat the tea tree oil wipe-over every fortnight, and keep your house aired. The mould will return (if at all) much more slowly if you use the tea tree oil method, and allow fresh air to circulate every day.
Shower cubicles and bath surrounds are also easy to keep mould free, but they require something ongoing which is stronger than just tea tree oil, as the damp and warm air is such an ideal mould growing environment.
With the window open for ventilation, spray the shower / bath / tiles once a week with the 'Dettol Mould and Mildew Remover' (again when no one else is around), leave on for the time stated on the bottle (a few minutes) and rinse really thoroughly (with the shower head or with a jug), especially if the bath will be in use later in the day. If you do this spraying/rinsing at least once a week and also keep your bathroom well aired daily, then the mould problem will be sorted.
The 'Dettol Mould and Mildew Remover' will remove the active mould spores and regular use once a week will stop any further staining, but it won't remove the staining from previous mould growth. I've not found any product that will remove the already-there black mould stains completely. Black mould stain removal requires DIY - painting over walls with a stain blocking primer before repainting or removing old, stained grout and replacing with new grout.
So, tackle the mould with bleach spray, apply tea tree oil and open the windows from now on. The black mould will not win!