Before this breakthrough, when my favorite solid deodorants crumbled, I used to shout, "That stinks!" in my head. Since I don't want to smell my own stank (or waste products), I had to battle that inevitable crumble with a makeshift solution: Using extra hose from holding broken soap to create a makeshift cap.
To make like me, grab those small pieces of deodorant and shove them back on top of the stick. Instead of reaching up an underarm with resulting bits all over clothes and the floor, I first slip a cutoff stocking foot over the top, twist it tight, and secure with a rubber band. This way the deodorant's still handy, the cover still fits — and you can keep a handle on your purse strings and your hand on the bus strap, too.