Thanks to Sarah for this Frugal Baby Tip!
I just put pieces of fleece on top of my daughter's pre-fold diaper. Most of the poop just rolls right off of the fleece, into the toilet...
If there is some poop that doesn't fall off, just shake off. I use a regular spray bottle on the hard stream setting and squirt with water -- it works surprisingly well. It even comes off of the diaper itself when the fleece doesn't catch it all. Hope this helps!