I have just found a Commemerative Coin, it is stamped - front "The Story Of Petroleum, Golden Gate International Exposition" with an oil rig in the middle and 19 on the left and 40 on the right. on the back is written a verse, not all is legable but it starts with "A dollar spent for petrolium products never......" thats as far as I can read without cleaning it, and maybe getting new glasses. Can anyone tell me about this? Was it from the fair? Is there anyone I can contact to donate or sell it? Thanks