What did Jehu do to the worshipers of Baal?

Answer: Killed them all

Jehu's guards and officers put all the worshipers of Baal to the sword.

“When he had finished making the burnt offering, Jehu said to the guards and officers, “Go in and kill them. Do not let anyone out.” So the guards and officers put them to the sword, threw the bodies out, and went into the inner room of the temple of Baal.”— 2 Kings 10:25 (BSB)