I was working on a media and image digitization project this spring and early summer. Some of the slides from 1960 had horrible color shifts. Here are two examples that I helped along in Photoshop and Lightroom. I did not take detailed notes on these but thought that they might provide an indication of what is possible without too much work. Obviously, other defects could have been reduced, like fingerprints, but there was an inadequate budget for this type of cleaning. Clicking on either image will bring up a larger version. I made the scans of the original slides on my Nikon Coolscan 5000ED.