Jerry Cruncher uses the term “honest tradesman” ironically. He is really a grave robber! He says that it would not do to recall people to life, because bringing people back from the dead would be bad business for a grave robber!
In Book 1, chapter 2, Jerry received a message to take to Jarvis Lorry. The message was “RECALLED TO LIFE” (p. 8). This means that Dr. Manette is alive. Of course, Dr. Manette never was really alive. He was just in prison in France.
It could scarcely be called a trade, in spite of his favourite description of himself as “a honest tradesman.” (p. 37)
Robbing graves just doesn't pay like it used to! In a way, Jarvis Lorry and Jerry Cruncher are both resurrectionists—people who bring others back to life. Dickens uses the ironic, basically sarcastic, description of Cruncher because he is a grave robber. He is also called a ressurectionist, though he does not literally bring people back to life.