O12-CU® Copper Remover Whether competition shooting or setting your sights on a trophy buck, a clean firearm can be the difference between success and failure. Don’t let copper build-up in your bore let you down in the moment of truth. The O12-CU® Copper Remover quickly and effectively removes copper fouling. This unique formula is biodegradable and with no harsh odor and also acts as a rust preventative. Removes copper fouling with ease, Prevents rust and corrosion for long-lasting barrel protection, Safe on all gun metals, Safe for the environment – biodegradable & free of ammonia, petroleum & has no harsh odor.