Keep the case closed when not in use so dust stays out, and wipe the clear surface with a dry cloth. Storing spare badges in a case makes it much easier to find the one you want when you change a layout.
How to organise
A common approach is to sort by theme or color per case, so a layout change is a matter of picking one case rather than hunting through a pile.
Practical note
Because the case protects the badge surface from scratches, it is especially worth using for badges you rotate on and off a bag regularly.
