Poop still in cloth fibers.. how to wash?

Hello! I am a first time mom, so this is my first time cloth diapering. I am using the Flip system (and like it), however, I'm struggling to get my 2 month old's poop out. I have been just tossing it all in the washer with detergent and putting it on the normal wash cycle with a pre-soak cycle. I have a high-efficiency top-loading washer. What have you other Mamas done? The wash gets most of the poop out, but after the 60-minute cycle, there is still some poop left in the fibers. I will put a picture with this post. Thanks!