If you have a place for hanging like I do in my closet than maybe this will work for you. When you buy flip flops never ever throw the plastic thing away they are hooked to when you buy them. The holders work wonderful for home storage. I liked this idea so much i actually went in Old Navy to see if they would sell me flip flop holders or refer me to someone I could buy them off of...well they couldn't, so now when I buy flip flops I make sure i keep the holder they come with. I have mine arranged on the bar according to color.
What you need:
A nail cleaning brush about a inch wide if you can find one, I believe I found mine at either Wal-Mart or The Dollar Store
A scoop of Tide powder detergent
A bar of soap you can use any kind, I happen to use Dove
A bathtub, or anything you can fill with water like a large plastic bin.
What to do:
Fill tub or bin with an appropriate amount (as much water as needed for the amount of flip flops you want to wash) of warm water
Add a scoop of tide to the water
Submerge all flip flops to be washed in the water and let soak for about 10 minutes.
Rub your nail brush on a bar of soap to get it good and sudsy
Scrub flip flop
Lay flip flop out to dry
Depending on how old each flip flop is, and what is on it as well as how hard you scrub in my experience each flip flop should come out looking brand new.