I based my date on the artwork !! The simple shapes are done in coloring book technique !! Could be decorated by almost anyone with a paintbrush !! No depth of color or detail to speak of just colors inside the lines !! Typical of many sold here during the 1970`s and later !! But do ask at the other forum,, we are only looking at pics you know !! Doesn`t hurt to double check !! Try some plain old windex and an old toothbrush to clean that bottom !! Or any good grease cutting cleaner !! Pour some in a shallow bowl with water and let it sit for about 5 minutes, then use the toothbrush to scrub !! May take more of the stain off the bottom !! Can also use a Teflon scrubbie !! But not on the artwork,, just the bottom !!