I have an AL mold that refused to break-in. I’ve ran about 8 casting sessions, and bullets still stick. The burrs from where the Cherry’s cutting edge exited the cavity would not break off from casting. So I took a strip of leather from a pair of Jesus sandals and scraped the leather against the burrs. I cannot feel any burrs, but the edges are still sharp. Still need to tap the handles a little to get the bullets out, but my production rate has doubled.