I save everything as I scrap, including cardstock scraps! When I'm not immediately using them, I place them in a gallon-sized Ziploc freezer bag by color. For example, all of my yellow scraps (even the patterned ones) are placed according to the color.
It makes it easier for me to sort them out as well as see what I have in what color! In addition, the bags allow convenient travel without spills or overflows!