There are some wonderful blogs out there on how to do various things in knitting that you wouldn't otherwise find out about. This is one of my new favorites - how to block acrylic yarn when you use it in lace knitting.
I personally prefer using wool for comfort shawls, because of the "lamb of God" thing maybe, and "good shepherd" - there are a lot of sheep references! Plus it has an earthiness to it, even when dyed bright colors, and it is a link to the past that reminds me that my problems are nothing new, people have been around a long time, and there is a continuity. Then for comfort shawls for people who are bedridden I always think about how wool can prevent bedsores because of its ability to cushion so nicely.
Still, there are times for using acrylic. Wool dissolves in acid, so if it gets vomited on it will get holes. Not good for someone going through chemo, or babies either for that matter. Some people do have allergies to it as well, and some may need something that can be easily laundered, for instance someone with an incontinence problem. So in our prayer shawl ministries let's give them the best that modern technology can offer - man-made fibers!
When you apply hot steam to acrylic, called "killing the acrylic", the fibers relax and then set in the new shape. You must be careful because too much heat can melt them together. But with a soft yarn like Caron Simply Soft, it makes it even softer, with a nice sheen and a lovely drape. And the good thing is, once you kill it, it stays that way! So it can be washed and dried and never needs to be blocked again! The other nice thing is if there is a texture in the pattern you like un-blocked, with acrylic you can block it selectively. I'm working on the Dorothy Day shawl right now (and haven't found any errors yet, hooray!) and am thinking of not blocking the candle flames, so they can stay puffy.
I just heard of an even softer yarn called "Oh My!" and will look into that one!