I've been on a roll, making a bunch of chemo caps. I'll drop them off at my local cancer center. I want to make some smaller ones for children and babies, and some larger ones in darker colors for men. I only use 100% cotton so they're comfortable for sleeping in, also.
I lost my brother 2 years ago to brain cancer, he'd just turned 46. Making chemo caps is a kind of therapy for me, and it's a way I can honor my brother.
Here's the easy free pattern I use. It has instructions for all sizes.
Crochet Hat Pattern #2 Free Crochet Pattern Oombawka Design Crochet
Shelley