What should I do if the metal shrapnel is difficult to clean?

1. Use a soft cloth or paper to wipe the fat, oil and lubricating oil pollution of the hardware shrapnel and then use a neutral detergent or ammonia solution or special scrubbing drugs to scrub; fingerprints, use alcohol or organic solvents (ether, benzene) , Wipe dry with a soft cloth and then wash with water; bleach and kind of acid attached immediately rinse with water, soak in ammonia or neutral carbonated soda aqueous solution, and then wash with neutral detergent or warm water. 2. The welding of the hardware shrapnel is heated and discolored, wash it with 10% nitric acid or hydrofluoric acid solution, then neutralize it with ammonia water, carbonated soda light solution, and then wash the stainless steel spring with water--specially used for washing medicine; organic carbide adheres and soaks in A hot neutral detergent or ammonia solution is then used to scrub with a weak abrasive detergent. 3. For labels and films, use warm water and weak scrubbing agent to scrub; for dust and easy to remove scales, use scalp, weak lotion or warm water to scrub; binder component, use alcohol or organic solution; surface contaminants of hardware shrapnel Use nitric acid (10%) or abrasive scrubbing agent to clean the caused rust-use special scrubbing chemicals to cause too much rainbow pattern, use scrubbing agent or oil to cause, use warm water scrubbing agent when scrubbing