Mickey Mouse Drinky Cup

Here we have a vintage Mickey Mouse sippy cup. It is a little soiled, but I'm afraid to clean it the graphic seems somewhat fragile. I wonder if anyone can tell me how old this is. In the bottom of the cup is an embossed image of Donald Duck, I digitally enhanced it so we can see it better. I don't remember how I came by this piece, maybe a flea market item. 50's / 60's ????