My favourite book at the moment is Bonnie Hunter's "Scraps & Shirttails: Reuse, Re-purpose, Recycle! The Art of Quilting Green". The book has loads of ideas for making scrap quilts.
Bonnie recommends pre-cutting fabric into useful sizes, so when you need, say, 2.5 inch strips you already have a box full.
My I Spy remnants are overflowing from all corners of my sewing room so I thought I would do some scrap busting. I'm trying out a pattern that uses 4.5 inch and 2.5 inch pieces, so I started cutting those first. I added 2 inch strips as well. Then some pieces were still too nice to cut into strips so I fussy cut 3.5 inch squares as well.
Ideally I would cut useful sizes from the fabric when it was new and not after it had been jammed into tubs six months before. But I am pleased with the morning's work. Now to get my swap blocks finished before tonight's patchwork meeting.