Willow
I am reluctant to "do" anything to my sheets other than throw them in the wash and MAKE BLOODY WELL SURE there is no bleach in there. We don't use fabric softener. That's another no-no.
You could try a cool iron to smooth out the roughness a bit, if that is an issue for you. If you or anyone else have anymore questions, you may like to ask at info@earthinginstitute.net I will see them much faster. I don't always check into this site.
Best wishes
Martin Zucker