Unless you have something specific in mind, I would just leave them as they are until you have need of that color fabric. I just used some scraps kind of like you are talking about to do a block for a swap. If I had already cut the scraps into a certain size they might not have been the size needed.
That being said, I'm most likely to cut fabric into strips rather than squares or triangles, since the strips can easily be cut down into rectangles, squares or triangles as needed.