<prompt> Human: Edit: thanks to everyone who commented! Got my answer and some pretty nifty ideas as to how to sort through it all. Removing the text of the question now just to avoid leaving a list of things to steal floating around on the internet :p  <response>: Consider the history of Van Gogh. He was not well known at all when he died. All it took was a cousin who also died left behind a wife who needed to make money and the only thing she knew what to do was run a gallery by helping out her husband before he died. She had a collection of Goghs work and started doing a biography on Gogh. The rest is history. If it wasnt for her, the widow wife of a distant cousin of Goghs who did not really know Gogh, we wouldnt have his work in museums today. so your first thing to do is look up and figure out the history of each painter and figure out where they stand in the art market these days. Some will be trash, thats for sure but theres still a market for artists who like to paint on top of pre-existing work. you got a lot of cataloging to do. even if it doesnt sell for big bucks, its a great way to pay respect to your grandparents years of curating by getting them all to new homes. 