Your scraps need to be cut into sizes that you actually use. I know that I make a lot of scrappy quilts (multi-fabric sounds more elegant) and use 2 1/2", 3 1/2" and 4 1/2" strips and squares all the time so that is what I now cut. I rarely use 3" strips or squares unless I am making 2 1/2" HST's so I probably wouldn't cut many of those. Having cut pieces in sizes you rarely or never use doesn't make a lot of sense. You need to know what sizes work for you and even if you'll use them otherwise you might as well box up those scraps and leave them on the guild "freebie" table so they are out of your quilting space.