I typically shake off the loose poops into the trash and then toss them into a laundry bucket until there's enough for a load in the washing machine. I use the hot water cycle, the free & clear detergent and some vinegar, then dry in the dryer without any dryer sheets.
In addition to its disinfectant properties, vinegar acts as a fabric softener. I'm currently using the All free & clear brand, but I've used Arm & Hammer's free & clear in the past. Just depends on which free & clear is on sale at the time I go to the store.
I stay away from commercial fabric softener for two reasons: it's all scented and I think it would be rather crummy to be a hedgie (whose nose is just a couple mm's off the floor) who can't get away from fabric softener smell... ever. Also, it tends to make the liners less absorbent. I'd rather the pee be absorbed and pulled away from hedgie than just sitting there on the top. Generally, unscented is the way to go for hedgies - whether you're talking about detergent, fabric softener, or dryer sheets.
I used to just wash in cold and hang to dry. But a couple of hedgie illnesses later has moved me toward the "kill bad mojo with heat" perspective.
