RE: Sharpening blades?
As someone else mention already, I sharpen my #11 exacto blades using #400 wet/dry sand paper. I do not remove the blade from the exacto knife handle. I keep a 3/4 inch wide by 4 inch long strip of the wet/dry paper handy, place the strip on a flat surface, and rub both sides of the blade against it. The blade lasts years and years. As an added bonus, when I'm "stropping" the blade I sometimes think back 65 years ago and see my father stropping his shaving razor (the folding knife type) on his stropping leather strap.