Use pure blades! A pure blade without a handle.
The blade can cut steel, so why can’t even the dried nail-free adhesive be removed? joke! Physical separation is the most worry-free. The shelf I bought was glued too close to the wall, so the shelf couldn’t be hung! It can only be dismantled! Originally, I wanted to buy a powerful glue remover and added it to my shopping cart. Before placing the order, I thought, let’s give it another try. It’s still the same tool, but the method has changed.
The trick is: use a blade without a handle! In this way, it can be manually separated like a "cutting machine" by walking closely with the board!
There will definitely be a gap in the nail-free glued items. Use the blade to rub and pull it little by little. Use something to pry the cut area (a spoon or a screwdriver will do, as long as it can be stuck there). Hold on, prying and pulling at the same time, and you will get to the back very quickly.