[colin bird]

Hi thanks for reading,just picked up a new job,bathroom Windows and bedroom windows on the outside have black mould /condensation marks caused by Windows being left slightly open as we all know this happens.
Normally is use  bio washing gel to remove the staining and usually works well but on this occasion even after leaving the gel there  to dwell  staining not really coming off,any ideas or products to use to remove would be much appreciated

[Smudger]

Pink stuff - really is a miracle cleaner

[Splash & dash]

Use a weak hypo mix that will kill the spores  and it will come off easily using WFP

[richard connett]

I’d go with pink stuff or astonish which I think is a bit better . They can be smothered on your brush or get up and do it by hand .  Last resort hypo in case the frames turn yellow

[colin bird]

Many thanks for the help I'm going to get some pink stuff as it sounds like it safer to use than hypo

[Simon Trapani]

I don’t bother with stuff like that. If it don’t come off with pure water I’m not interested.

[Bungle]

I don’t bother with stuff like that. If it don’t come off with pure water I’m not interested.

Same