Love Rusteprufe and use it on everything? Then the quart jar is a must for you. Use your quart bottle to wet a patch to clean from breech to bore. Our solvent works perfectly to eliminate all types of fouling while the oil protects the barrel from rust, all in one application. Also works at the same time to lubricate and protect the action. When your chamois jar starts to dry out pour a little bit on the felt disk to reload your chamois. Rusteprufe should be used on all metal parts of your weapon inside and out!