[CarRamrod]

The best thing I've found after dealing with mold is a simple 3% hydrogen peroxide solution that is sold in any drugstore. Put it in a spray bottle and soak the area deeply enough and it should kill it down to the roots.

And a plus is that when it breaks down the only fumes it gives off is pure oxygen, unlike other cleaners like bleach. It did such a good job that I use peroxide as a general purpose cleaner now.

I will add one note that you should rinse your hands regularly if cleaning with peroxide. Just a few days ago I had a leaky spray nozzle, and the peroxide was on my finger long enough that it was able to soak in. It turned my skin chalk-white and caused an uncomfortable bubbling sensation inside my skin. I had no idea it was even a reaction that could happen. It only lasted for a few hours, but it's not something I would want to happen again.

[sigmoid10]

You should note that while a single use (like to kill mould) may be fine, regular use on stone, metal or wood (i.e. most stuff in a bathroom) is not recommended because it is a powerful oxidizer that will considerably damage these surfaces if used regularly. That's because it releases hydroxyl radicals that destroy not only molecular bonds in stains and microorganism cell walls, but also attacks treated surfaces and corrodes metals.

[CarRamrod]

Duly noted.

[W3zzy]

Good pointer. Bleach isn't more effective than regular soap or hydrogen peroxyde.