A razor blade is gonna take you a while. If you want to get it into an album then a hack saw would work fine with a way to pry the pieces open.
Yes and the best in my opinion. You hold the slab in one hand and nip off the edges. At some point the top and bottom of the slab will be free. Use eye protection. You can buy end nippers in several sizes. The older you are the longer the handle needs to be.