Heat, humidity and light can destroy your transparancies, so store them in a cool, dry place in closed boxes. When using glass mounts, fungus can become a problem, therefor glassless mounts are better for long time storage, but of course then you have to watch out for fingerprints plus slides in glassless mounts may "plop" during projection (see my remedy under "Slide projection suggestions") If you are looking for a basic system and your slide projector accepts universal trays, then use the Leicaboxes containing 2 universal trays for 50 slides. They are simply the best and not much more expensive than other brands.
