To find out the source of odor, the general metal mold is odorless, mainly the oil used in the production process. The most commonly used cleaning agents, rust inhibitors, lubricants and release agents in mold factories are best to choose environmentally-friendly ones without special odor. If you are greedy and cheap, the things you buy are not environmentally friendly. Generally, it has a strong pungent smell, which is harmful to people's health.