When I was estate administrator for my aunt's property, I came across artwork, sketches, personal notes and hand-written instructions and painting tips, most by Doris Grasso and a few by Wayne Morrell. My aunt was an artist, and she vacationed in Rockport, MA where she met these people and became friends.
I've hit a dead end here (near Saratoga Springs, NY) since almost all local art galleries are closed because of COVID restrictions. I did contact two art museums in Cape Ann. I am still waiting to hear from one and the other wasn't interested in them. I don't even know if these "non-typical" artist's artifacts have any value. Here are just a few samples: