I usually sort and store my swaps in the aqua punch box tins (which you can buy seprately now). I sort them by season. I have a tin for christmas and winter cards, one for spring flowers, one for everyday(weddings, birthdays, etc. and the other for fall holidays (like halloween, school stuff, and thanksgiving). So when I have a party or a class all I have to do is take out the coordinating seasonal punch box and let the customers flip through them
When the stamp set retires that is used on the card or when I need to purge some swaps I bundle about 5 of them together with a strip of paper saying thanks for your order and give them to customers with their order. They LOVE them!!!