not worth the candle

noun

1. a cylindrical mass of tallow or wax with a wick through its center, which gives light when burned
2. anything like a candle in form or use
3. 1. candela
   2. until 1940, a standard unit of luminous intensity equal to a certain fraction of the candle power of a group of 45 carbon-filament lamps kept at the National Bureau of Standards; international candle

transitive verb candled, candling