I have two cars that I take care of which have approximately 10-year old coated leather. Both are GM vehicles; A '99 Buick Regal and a '97 Olds Regency. Everything I have used on the seats leaves a pasty residue on the towel that is the same color as the leather. Also, everything causes the leather to be sticky, almost like it's wet. I know the leather on both cars has been negelected. Is there anything I can do to bring it back to life. Otherwise the leather is in decent condition.