I'm doing a similar project right now and believe it or not, the black gooey stuff comes off with soap and water! I let it sit for 5 minutes and it scraped right off! My husband was sweating bullets just chiseling 8 square inches in 20 minutes--I had 4 times the area done in half that time. I'm still getting ready to sand, but I think that the more glue I can get off, the easier the sanding will go. I am going for a rustic look (70 year old home)--don't know if this would work for a cleaner look.