Head for the Gold Coin Ruins!

Head for the Gold Coin Ruins! is a limited-time event that occurred during September 2015. Along with the September event of Collect Mystery Boxes event, it sought to promote the usage of Adventurer Cookie for both old and new players.

This is also one of the very few events that tweaked the gameplay for Adventurer Cookie. Instead of getting Jellies in the Hidden Ruins, players can find a huge amount of coins inside, making him a Coin-Farming Cookie during the event period.

Coin Farming for Adventurer Cookie
There is not much strategy involved in this - just try to access the Hidden Ruins as much as possible, and of course, play in Escape from the Oven with the Double Coins Random Boost.

As Adventurer Cookie, you want to be able to get to the Hidden Ruins as quickly as you can and explore it as far as you can before you are dragged back up above if you wish to maximize Coin farming with him. Because of this, using treasures that gives Higher Base Speed and a Coin Bonus, such as Golden Syrup Filled Piece of Cake or Slippery Golden Banana Peel will be ideal. You are going to need some degree of Magnetic Aura to be able to collect Coins, but due to how they are set up in the ruins you do not need a huge Magnetic Aura - just a Angel Cookie's Rainbow Feather will do - although it's not completely necessary - you can try to do it without any Magnetic Aura at all!

As for Pets, you can either go with Coin Scale as it will convert all the useless points into Coins, the Pistachio Firefly or Mr. Fa-Sol-La-Si as they will help you get to the ruins faster and explore the ruins longer (if the Pet's blast carries into the ruins) on top of giving you Energy/extra Coins.

Trivia

 * Apparently only Adventurer Cookie can benefit from this, as he is the only cookie who have access to the Hidden Ruins where the coins are located.
 * This is the only event which triggers the modification of a Cookie's ability.