2. When there is ballpoint pen oil, wipe it off with an eraser as soon as possible. If there is grease or dirt, scrub it with soapy water first, and then clean it with clear water.
3, stained with beer, sodium carbonate (baking soda), coffee and other substances, first scrub with soapy water, and then wash with water.
Washing leather with fresh milk will make leather more shiny.