Here's what I do.
I flip them inside first and pick out all the pods in them and give the fish a treat. Then I rinse them in the sink. and get as much of the "gunk" out of them. Then I put them in a 5 qt. ice cream bucket with water and a few capfuls of bleach. I let it soak for about two days then rinse it out again and hang it up to dry on the back porch. I use some clothes pins to attach them to a clothes hanger to dry. The sun will deactivate any residual chlorine. I have two sets of filters and I alternate them in this way.
Gary
125 SPS, 75 gal. LPS/softie reef, 9 gal. Nano