I've now made several loaves using my bannetons. I am using some scraps of linen inside the bannetons well floured. The linen peels right off the sticky loaves with no trouble. I can highly recommend using 100% linen. I've read people asking other bread makers about how often to wash these linens. The questions was met with surprise and humor. None of them ever wash their banneton linens. It's like asking, "do you wash your cast iron pan with soap?"
Bread is like the sun. It rises in the yeast and sets in the waist. Unknown author
Initially, this bit of information tested my urge to clean everything after each use. But the linens really do perform better with a few layers of flour on them. The same goes for the bare banneton baskets (if you want that artful coil pattern on your loaves) and the baker's linen used to form Batards. Like you said, Sylvia, it's like a good seasoning on a cast-iron pan--you don't want to strip it away. I'm in the habit of using a soft bristle brush to gently brush off large accumulations of flour from banneton baskets and baker's linens after each use, and then they get tucked away for next time.