1. Look at the color. Pure oil should be colorless.

2. Look at the transparency. Pure oil should be transparent.

3. Look at the sediment. The sediment is commonly known as oil feet. The main component is impurities, which sink to the bottom of the oil under certain conditions.

4. Use clean chopsticks or a glass rod to take one or two drops of oil, apply it on your tongue and taste the taste carefully. Oil with a sour taste is an unqualified product, oil with a burnt and bitter taste has gone rancid, and oil with a peculiar smell may be adulterated oil.