That's a good tip. I've often wondered how the blue stuff would work but haven't had the occasion to try it. I have successfully removed adhesives with lighter fluid with good success, too.
While I'm not a leather worker close to those who post on here, I have had some experience with around-the-house solvents.

I might suggest a product called "Goof Off". I have found it removes many adhesives and hasn't damaged anything I've used it on. I've made many OOPS that it has helped me recover from. I just don't know if I've ever tried it on leather, so proceed with caution.