How important is it to soak nappies in some kind of sterilising solution such as napisan etc.? Is it just dirty nappies or is it important for wet nappies too? I wash nappies at 90 degrees but don't soak them, will that kill all the nasty bacteria? Also I sometimes cold wash wet nappies with the normal wash, is that ok? There have been no noticeable problems, but have I just been lucky, should I really be 90 degree washing all nappies?