Cooking oil is not dangerous. If it's gasoline, you won't be allowed to bring it.
You can even bring wine, let alone oil.
Here are his requirements.
1. The free weight of passengers' belongings is 20 kg for adults, 10 kg for children (including free children) and 35 kg for diplomats. The length and volume of personal belongings should be suitable to be placed on the luggage rack or under the seat, so as not to hinder other passengers from riding and passing. The external dimensions (the sum of length, width and height) of the articles carried shall not exceed 160 cm. Rod, column, tower ruler and other rod-shaped items shall not exceed 200 cm in length.
2. All dangerous goods (detonators, explosives, firecrackers, gasoline, kerosene, calcium carbide, liquefied gas and other explosive, flammable, spontaneous combustion and highly toxic substances), articles that hinder public health, animals and articles that damage or pollute vehicles (such as chickens, ducks, geese, dogs, pigs, monkeys, cats and snakes) are restricted by the state. However, under the condition of ensuring safety and hygiene, you can carry the following items:
1, 20 small boxes of safety matches, 5 gas lighters.
2, no more than 20 ml of nail polish, gloss remover, hair dye. Alcohol, perfume and cold perm solution shall not exceed 100 ml. Household sanitary insecticides and air fresheners not exceeding 300ml.
Soldiers, militiamen, public security personnel and hunters carry guns, bullets and grenades.
4.20 newborn chicks.