Never used, but washed Natural aluminum commercial bakeware is made of pure aluminum which will never rust for a lifetime of durability • Baked goods rise and bake evenly due to aluminums superior heat conductivity and the reinforced encapsulated steel rim prevents warping • Easy clean up, hand wash only. Nylon, wood, or silicone utensils are recommended • Pan exterior dimensions 15.63 x 9.63 x 3.25 inches and interior dimensions 13 x 9 x 2.5 inches • Proudly made in the USA by Nordic Ware