I have a Donald Duck child’s warming dish that has a “U” mark on the bottom. If you’ve seen one, the duck head comes off and the hot water is put in the dish to keep the food warm. It dates back to 1940’s and before. All I can find out about it is that Hartscraft was the designer, but had other manufacturers make various products for them. I can’t find any with the “U” mark. If you turn it upside down, it looks similar to a horseshoe, but really doesn’t measure up to that symbol. Please let me know if you know what mark this is and what the value might be.
Thanks.