To keep the bottoms of my handbags flat and the insides clean, I make a template of the bottom of the bag by turning it over and drawing an outline with a marker onto those flexible cutting boards or clear plastic place mats and then cutting it out and placing it inside on the bottom of my bag. It is easy to do and cheap. Avoid sharp edges and round off the corners. I sometimes cover the edge with colorful masking tape, so that it is smooth, but not always. They add no weight, but really help keep it clean and flat. Even helped a few older warped bags that my sister had not stored properly. I, too, store my bags stuffed and in pillow cases or sleeper bags.