Recently my youngest son sowed some cress seeds, the instructions said to place the container in a black bag, we did and a few days later when we took them out they were covered in a white fluffy fungus(i think this is the same as damping off ??? ). I was going to throw them away but sitting on the side was a can of Dettol disinfectant spray, i gave them a quick spray. The next day they were clear of the fungus. It's a week later and they are still growing well :)
I did the same with my new heated propagator, when i took the lid of after about 3 days there was the same fluffy fungus, a quick spray and a day later there is none in site.
I'm not sure if this has been mentioned before or if it would be classed as non-organic but it should be safe as it's used for disinfecting food areas.
Neil