Harmy said:

Doing this kind of thing in After Effects is less than ideal, since it was never made for film-restoration and I also tried PF Clean and I just couldn't get it to work but I couldn't afford the full version of PF Clean anyway, so I'd really like to learn how to do by myself what Laserschwert has been doing for me so far, so that I don't have to bother him with it. So I guess my question really is how to do this sort of thing in Avisynth.

Before moving on to Avisynth suggestions, I'd like to ask: Do you know that The Pixel Farm is selling PFClean at a reduced "education discount" rate? It's $167 USD. I don't know if this will make it any more affordable for you, but I figure it's worth mentioning.