Vintage Shell Oil Double Sided Porcelain Sign Clamshell GAS SODA 25" x 24". The item "Vintage Shell Oil Double Sided Porcelain Sign Clamshell GAS SODA 25 x 24" is in sale since Wednesday, February 07, 2018. This item is in the category "Collectibles\Advertising\Gas & Oil\Merchandise & Memorabilia\Signs". The seller is "asseenonpawnstars" and is located in Brodhead, Kentucky. This item can be shipped worldwide.