These advertising words are usually written with a marker. Like ink, ordinary cleaning agents can't remove it. You can use gasoline, alcohol or go to a paint shop to buy paint thinner (also called Tianna Water, banana oil). If the paint shop asks you what polyester, PE and nitro you want, just ask nitro, because this is the cheapest. Generally every 500ml 3 yuan. Others are a little more expensive and have the same effect.

When in use, cotton cloth can be dipped in a little gasoline, alcohol or diluent and wiped directly on the internet. Will not damage the bottom blank (you can wear rubber gloves to avoid bringing odor to your hands)

Good luck!