@ffffff. Combustion is a good program. For mac users I recommend Shake but in general software only get smaller differences in the video such as blobs and spots. Problem lies in larger scratches and smudges and for these its the job for an artist. Its basic retouching.
I'm working on a demo at the moment and I can see it will take time. I grabbed a few seconds from the "Return of the Ewok" feature that OCP released. I can't work on the telecine bits. The just isn't enough information to go on. And by the looks of it it wouldn't result in anything magical. But then there is the Hyperspace clips which obviously have so much higher quality and in these cases the result is much more visible.
I'm going to post a before and after of one specific frame which I just did:

I made this using bits and pieces of information from the frame just before.
Obviously this process is so time consuming that it should be done with very specific purpose.
For instance...If someone were to find the original tape for the above mentioned "Return of the Ewok" then I would definately consider doing some heavy dustbusting on it.
I don't know if Puggo ever got around to completing his 35 mm digitization but this would also be one of those projects that I would consider putting down serious time on. Just for the heck of it.
@Vaderios I'll post my Ewok demo as soon as I am satisfied with it!