Chemically cleaning the metal is performed by using a slightly alkaline detergent cleaner that is formulated particularly for cleaning guns prior to bluing. It removes all grease, dirt, and crud and puts that material into suspension. It is strong enough to do the job right yet it is totally safe to use and harmless to the steel and of course us. At the end of this phase, all parts are considered surgically clean. Ensuring the cleanliness of the parts is crucial to ensuring a beautiful finish.