H2O2 was delivered very quickly. I used it at 10% - thats a 1:3 dilution- to treat mould infestation in the attic. Needed to wear protective clothing, face shield and a good dusk mask. Don't breath it in and avoid contact with skin, especially eyes. I sprayed it liberally onto the mould. 1L of the 35% solution treated some 15 square meters. Awesome results. Mould fizzled up and completely dissappeared. The good thing is that H2O2 degrades into water and oxygen within an hour or so, therefore I have no poison in the attic. I then dried the attic by ventilation as much as I could. Next step will be to apply boric acid to protect the wood. Need to wait for drier weather. Synopsis: H2O2 is a very powerful chemical weapon against mould.