Over the next few decades, it's estimated that over $90 trillion in assets is going to be passed down from baby boomers and the silent generation to millennials and Gen X. You know what else they're passing down. An avalanche of stuff.If you're lucky, it's just silver, china, brown furniture, and junk drawers full of batteries and flashlights. But boomers tend to collect lots more things like model trains or Hmel figurines, guns, baseball cards, and comic books. People are calling this the great stuff trans ...