Dont beat your self up over this, we have all I am sure had a similar experience (at least us oldies have). I have for example, only negs from about 1979, all my previous negatives were seriously damaged by condensation as I lived in a caravan back then. Some of these I have kept but they are in poor condition. I have scanned many of them and using Paint.Net (a free programme) I was able to clean them up. i recommend this programme just Google Paint.Net and down load it for free.