While most methods for cleaning sticky marks, such as those left by labels, are not suitable for use on delicate surfaces such as leather upholstery, a focused squirt of a normal wax-based furniture polish will quickly dissolve the glues, and should be safer than most other methods.
The tips, hints and ideas at TipKing are vetted prior to publishing however some methods remain speculative in their own nature; therefore the information should be used responsibly and at your own discretion. The Information is displayed on an "As Is" basis, without warranty. Full disclaimer