Here's an idea. They created the National Film Registry to preserve films the public recognized as 'important'. How about we now propose the 'National Film Registry Fund'. Using Kickstarter.com, people could choose any of the films selected from the Registry and give money to see that the print which was supplied gets the chance to be preserved in the method the Library of Congress sees fit, with the caveat that when those criteria is met that preservation effort gets put back onto the shelves or the public domain, irregardless of it's current copyright status. (generally those films are all expired from copyrights original length)
I guess as an exercise, it might be interesting to run through the NFRF Kickstarter idea using SW, maybe set up a 6 month to 1 year window for people to pledge, set a maximum pledge (some proportion of the BR set or a common movie ticket price), and see how far things get.
Then ask experts like someone at the LoC, Lowry, Harris, etc. to explain how those funds would get used, and if the public could help out. (could some system be set up like SETI, where the public's computer are used for processing work. Maybe frames could be placed online and people could point to the dirt and some program would automatically take the info from the frame before/after to fix) yeah that's farfetched.
Maybe the time to attempt the pledge fund part would be the year before the run up to the 3D releases. Could also just be done with a petition, signing the petition says you contribute one movie ticket amount.