Over the 20 years this site has been running (yes, the archives only go back to 1999, but I started the site back in 1995) I have changed the bit-rate that I record the files at many times. Comparatively, most of the really old files sound like crap compared to things that I've posted in the past year.
I am slowly going back through the old clips and re-recording them to be of higher quality. This is not something that can be done quickly. On average, it takes me two to three times the length of a show to record the clips. So a two-hour movie may take me four to six hours to go through, record a clip, trim the ends so they fade-in and fade-out cleanly, try to reduce hiss and hum (if it can be done without degrading the quality and making it sound metallic), and then compress the file for use online.
Here are shows that I've already finished upgrading: All About Eve, Back To The Future, Part I, Batman Begins, Commercials (Mystery Date), The Great Escape, The Lost Boys, The Madagascar Penguins in a Christmas Caper, Mulan, Reefer Madness (aka The Burning Question, aka Tell Your Children), The Terminator, Zardoz.
Here are shows that I've updated some clips, but not all of them yet: 2001: A Space Odyssey, 3rd Rock From The Sun, American Dad!, Archer, Batman: The Movie (TOS), Battlestar Galactica (TOS), Farscape, Phantom of the Paradise, Star Trek (TOS), Star Wars: Episode VI - Return of the Jedi, Terminator 2: Judgment Day, That 70's Show, Twin Peaks.