Blech. I've always just rinsed the in hot water. No need to introduce detergent. It will likely leach into your beer. You can use star San or one step if you really want but as long as you rinse them good and air dry they should be fine. They get sanitized in the next boil anyways
If I am using them in the boil I just rinse real good with warm water. If I am dry hopping with them I boil them first to make sure they are sterilized. That way if there is any gunk it will kill anything on it.
I empty & rinse them. Then boil in a small saucepan for 10-15 minutes. Then place them in a small tupperware container & cover with PBW,sealing it with the lid. Let sit for a week or so to soak the stains out. Rinse,wring out,& hang to dry before storage.