My mom had tons of old comics in her parents' attic - there was probably a Superman #1 in there. My grandpa threw them out. They probably could have paid for my entire college education.
I have a Shirley Temple dish (my mom's obviously) from the 1930's that I do wonder how much it's worth. I also have some kitschy 70's things (like Fred Flintstone glasses) but I wouldn't ever sell those - they're special to me. My heirs can do what they want with them.