The short answer
Ventilate, wear gloves and a mask, and wipe it off wet with a mould remover or diluted bleach. Never brush it dry, which puts spores into the air you are breathing.
- Open the window and wear gloves and an FFP2 mask.
- Wipe the area with a cloth wet with mould remover or a dilute bleach solution, working inwards so you do not spread it.
- Bin the cloth, do not rinse and reuse it.
- Dry the area thoroughly and keep it ventilated.
- Then deal with the cause, or it will be back within weeks.
What will ruin it
Never mix mould remover with anything else. Most are bleach-based, and bleach with an acidic cleaner releases chlorine gas at ordinary household concentrations in an unventilated bathroom.
Why it works
Killing surface mould does nothing to the moisture that grew it. On porous surfaces like plaster or fabric the growth has roots below the surface, so wiping the top is cosmetic even when it looks like a complete job.
Household chemicals can be dangerous in combination. Never mix them, keep the room ventilated, and test anything on a hidden patch first. Full disclaimer.
More damp
Which kind of damp you haveHow to stop condensation on bedroom windowsWhere mould appears, and what that tells youIs a dehumidifier cheaper than heating the roomWhat to do about damp in a rented homeAppliance Running Cost CalculatorWhat any appliance costs per use, per week and per year, plus eighteen worked out for you at today's rate.Open the calculator →