If you have portable usb drives for your computer they can get lost in a bag or worse yet, they could get dirty and damaged.
Slip those drives into a casette case and they're safe and protected, plus the case is easier to find in your bag.
Along those same lines, if you have a memory cards or card readers for your digital camera, they will store easily in a casette case too.
Stick bandages, alcohol swabs and ointment in a cassette case and you have a little first aid kit for your desk, your purse or your glove box!
Or slip stamps and return address labels in there so you can find them easily when you need them.
Along those same lines, if you have a catchall drawer in your house, line up several cases and you can sort rubberbands, paper clips and other little items that can be hard to find when you need them.
And you thought you were going to throw these away. I'm Mrs. Fixit and it's just that simple!