It is a locution with many local variants. See "spend gunpowder on chickens", "spend gunpowder on zamuros", "do not spend gunpowder on chimangos", "spend gunpowder on zanates", "spend gunpowder on salvos".
SPEND GUNPOWDER IN ZANATES used like this in Nicaragua and Mexico: see SPEND GUNPOWDER ON CHICKENS. The ZANATES is an inedible bird from Mexico and Central America. Venezuelan variant: spend gunpowder on zamuros.