That plow, that harrow, remember in the war we planted mustard? Remember a fella wanted us to put in that rubber bush they call guayule? Get rich, he said. Bring out those tools – get a few dollars for them. Eighteen dollars for that plow, plus freight – Sears Roebuck.
– John Steinbeck
The Grapes of Wrath, Chapter 9. The farmers sell off their belongings to second-hand dealers, who offer them pitifully low prices. They have no alternative but to accept, because they need the money to finance their trip to California. The plow and harrow were tools for survival and living, so it is ironic that during the war they were involved in the production of mustard gas, a type of chemical warfare used to kill people.