If you produce more that you consume, you will sell the surplus of production every tour and will keep the corresponding ecus. There is however a 35.000-ecu limits / tour maximum. You can never resell more that this limit. So, it is judicious to produce always more to never be caught up by the needs of your army, which will increase during your progress in the game. Think of checking your production regularly.
Subject: The Sell foods 
Tue Dec 15, 2009 12:50 am
