Other uses of pencil lead
The lead core can not only be placed in the pen case, making it a tool for calligraphy and painting. And it has another purpose-as a lubricant.
A rusty lock cannot be opened. Adding a little pencil lead powder to the keyhole can often open the rusty lock. The pencil lead can be unlocked because:
1. The pencil lead contains graphite, and graphite has lubricity. The pencil lead can lubricate the rusty lock.
2. Graphite has a high melting point. As a lubricant, it is especially suitable for machines that work at high temperatures. At high temperatures, general engine oil will decompose, however, graphite is very stable and continues to play a lubricating effect.
Graphite is a scaly solid with metallic luster. It is composed of carbon elements and has a very stable structure. There is nothing in the human body to destroy it, so the pencil lead is not toxic.