2. There is a more advanced method: dip a cotton swab in isopropyl alcohol and lightly coat the font. When the font color is blurred and the pigment is separated from the cup body, clean it with water and wipe it with a paper towel without hurting the cup body.
3. Isopropanol is an organic compound, which is an isomer of n-propanol, alias dimethyl methanol and 2- propanol, also known as IPA in industry. It is a colorless and transparent liquid and smells like a mixture of ethanol and acetone. Soluble in water, but also soluble in most organic solvents, such as ethanol, ether, benzene and chloroform. Isopropanol is an important chemical product and raw material, which is mainly used in pharmacy, cosmetics, plastics, spices, coatings and so on.