O12-C® Carbon Remover Carbon build-up can cause jams and affect the accuracy of your firearm. To keep your firearm functioning in peak condition, use O12-C® Carbon Remover. This unique biodegradable formula quickly and effectively removes carbon fouling. Cleans Modern Sporting Rifles/ARs with ease and is recommended for use on bores, bolts, pistons, cylinders, and any other areas with carbon build-up. Removes stubborn carbon fouling with ease.