I have a couple of acrylic/wool blend (15% wool, I think) soakers that I made, and although they don't have the same nice feel that our all-wool soakers do, they seem to work fine. I do tend to change wet dipes quickly, and I haven't yet put any of my soakers to the nighttime or several hours in the car test! I also let covers air out between diaper changes, so nothing gets too stinky. I haven't lanolized anything yet, wool or blend, and it all works great. (I'm still in the slightly-amazed-that-knitted-soakers-are-water-repellent stage!
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Given that I seem to prefer really expensive wool when I buy 100% wool, the acrylic/wool blend is a very nice, economical choice for us, and I love knowing that if (heck, when!) it gets dirty/poopy, it's no big deal to get it clean!