+1 Great resource, I've been using these to keep my originals from wearing out or getting damaged, as well as games I don't have the manuals for.
Here are some scanning tips I use on my cover project stuff that may help out.
1-Put black paper behind the manual pages, this helps reduce images and text from the other side to show through. Also helps reduce glare around the sides if the black paper is bigger than the page. (I got some black paper at an art supply store)
2-Put something flat on top of the page with a 2.5 pound weight on it for better/flatter compression, some scanner lids don't do a very good job.
3-Descreen scanner option should help on these if your not using it already.