Obviously there's more than one way to do it successfully. I've degreased them, and other times simply applied it to a fresh sanded surface. I've sanded them with different grits of sandpaper, and even scored the back with a toothing plane blade. None have lifted.
I think keeping the wood uncontaminated and good sizing with glue are important. I never touch the gluing surface with my bare hands once I start sanding, and do all the prep on glue-up day right before I begin. I use hide glue.
