[Pj]

Anyone know how to clean up black mould from white internal glazing mastic?

There must be a product surely?

[Adam Boss]

mould tends to affect the mastic as it does in bathrooms, normally it has to be replaced.

[Wizard]

You need mould resistant mastic or silicon. Prevention is better that cure.

[andyatkinson]

I did this the other day, had to charge £200 to do inside and out of 12 normal windows. tried a ew things, the only thing was bleach applied thick to seals with a cloth and then a hard bristled scrubbing brush like the dish washing kind, and keep dipping it in a cup of boiling water, 6 hours later, done

[ps outthere]

There is a product that works very well on kitchen and sink silicone, also on grouting, it is Dettol Mould and Mildew spray. I have bought it at Asda and Tesco.
Paul

[niceandclean]

You need mould resistant mastic or silicon. Prevention is better that cure.

Yeah, just pull it all out, and get some mould resistant silicone and re-apply.