Method 1: Prepare more egg shells, then crush them and place them in oil bottles or oil drums. Then add hot water and shake them vigorously. After a few minutes, the oil inside will come down. Just rinse them again.
Method 2: Prepare some fine sand and baking soda, put them in an oil bottle, oil drum, add hot water, shake vigorously for a while, and then rinse them off.
Method 3: Pour a little dishwashing detergent into the oil bottle or oil bucket, then pour it in boiling water for a while, shake it a few times, pour it out, and rinse. If there are no oil deposits in the container, you can do this.https://www.fhpails.com/