I'd suggest mineral spirits, otherwise known as paint thinner, available at any hardware or paint store and cheap.
Soak some into heavy paper towels or on a rag and scrub away. Won't do a thing to metals, but will remove most adhesives, and far better than rubbing alcohol or the like (although rubbing alcohol does go after some kinds of gunk that thinner won't). Be patient. You could even try a plastic kitchen scrubbing type brush, which is softer than aluminum, but harder than adhesive gunk, and could help get stubborn stuff off.
You can use gloves if you want, and probably it would be better, but thinner won't really harm you, other than making your hands reek a bit and drying out your skin. It's relative harmlessness makes it easier to use than some industrial strength products.
Good luck.
Ken Bensinger,
Brooklyn, NY