Been going through a lot of my dad's old transparencies from when I was a child, some dating back as much as 30-odd years. I'm really disappointed to see that some are succombing to what I'm guessing are fungus attacks, indentified by random blue dots on the slides. I assume this is irreversible on the slides which have already been effected, but how can I prevent it from getting worse? The slides are stored in a warm but dry environment (in boxes of slide-trays on my wardrobe in my bedroom). I don't want these treasured photos to disappear before my very eyes The worst-effected slides are those which haven't been glass-mounted. Would I be wise to clean all the slides with isopropyl alcohol and glass-mount the lot? It could take me a while: there's about 1,500 of them!