Anyone have any suggestions for how to deal with itchiness from insulation?
Hard to fix once it's happened; prevention is a pretty good cure.
Insulation is nearly microscopically thin glass fibers that get stuck into the skin and jostle the nerves, thus causing the itching. So the goal is essentially breaking off the protruding ends of the glass fibers which catch clothing or bedding, or to pull the fibers out completely. Water or soap or lotion won't do anything, because the fibers won't dissolve; mechanical action is the only thing that will work.
Basically, removing the outer layer of dead skin can remove the fibers stuck there. Baking soda or any other similar solution like pumice can act as an abrasive. Sandpaper or an emery board can also do the trick, but it tends to remove hair, so that's best for small areas with just one or two itchy spots.
I've had success using a bare razor blade or very very sharp knife, and scraping the blade across the itchy areas nearly at right angles to the skin. That works without removing hair.
A good solid scrub with a loofa or similarly rough scrubbing pad while taking a hot shower also works. It's not the temperature change, but the water softens the skin to make it easier to scrape off the outer dead cells.
Hope this helps...