Do not use.
The word "use" usually needs to have something after it:
Do not use this medicine if the seal is broken.
But in written notices, people often leave out certain words that aren't necessary. Here are some examples of similar notices:
Beware of dog
Do not close
Falling rocks ahead
Notices like these leave out objects ("this medicine"), "be" verbs ("are", "is", etc.) and articles ("the", "a").