you can use a damp cloth dipped in a warm bowl of 10 parts water to 1 part washing up liquid. wipe over the glass and the plastic frame twice a week during the winter months. try leaving the window open on the lock position(the window should only be open by about a half to three quarters of an inch) this should reduce the room temperature therefore reducing the air moisture content.(condensation occurs at 100% air moisture content, mould and mildew however occurs at around 68% content) this means that if you constantly have condensation you may or will probably have mould or mildew present. consider increasing your loft insulation,having cavity wall insulation injected,a window or wall vent installed, and having a dehumidifier placed in the offending room. they cost roughly the same as a fridge to run(around 2-3p/hour) and cost between £100-160 to buy. in a downstairs room do all the above(apart from loft insulation)also make sure there are enough air bricks and that they are clear of any debris.(ther should be one air brick every eight foot on an exterior wall) keep the bathroom door closed and the window open when taking a bath or a shower, also try to not dry clothes inside the house,try using a tumble dryer with an external vent fitted. a dehumidifier in an average size three bed semi should prevent condensation occuring in any room. should you find any black mould present you should use a mix of 1 part bleach(domestos)to 20 parts water, use a plant spray bottle to spray directly onto the mould, leave for only 1 minute then wash off with a clean rag dipped in clean warm water, once dried you should paint surface with a damp seal paint,(not a stain blocker) once this has dried you can then decorate with emulsion or paper. if you have mould on your wallpaper you can use the bleach/water mix directly onto the paper, wipe off as described above this should cure your problem.
dampfix uk, December 2009