I use Very Hot soap and water to clean the barrel, and boiling water to flush the barrel and have never had flash rust. Of couse, I have leather gloves one, and once the barrel is flushed, I dry patch it and then run sheath through it. I've checked them later but never found even a hint of rust.Once the rifle is cool then I put the rifle back together and everythingstays just fine until the next time I shoot.