Pickpocket the elven workers from all the different clans in Prifddinas. Note that the total amount of money made is a lot more considering this only is based on the coins gained. Head over to Prifddinas, use the lodestone if you have it unlocked. Walk to one of the clans and start pickpocketing the workers affiliated with the clan. Once you are caught for the third time move to the next clan and start over. You can work your way through the clans both clockwise or counter-clockwise. The following methods will optimize the stealing itself: