The Incredible Neat Video plugin for NLE's is a true restoration tool. This excerpt from an old 8 mm movie of mine shows a scene before and after, and then a split screen comparison. Here I use a quick, very aggressive setting, so some detail is obviously lost. By tweaking shot by shot you can get even more incredible results.
This cleanup was done on very difficult material: an 18 fps to 25 fps interlace telecine of the 8 mm film. If the source had been a frame by frame scan, the results would have been even better.