Almost anything corrodes very easily under human skin contact. If you take a pH testing kit, and put a drop on your skin, you'll notice you're pushing fairly acidic levels.
I destroy guitar strings on a near-weekly basis, despite all the anti-corrosion plating tech they have.
No, annodized aluminum is very resistant to corrosion. Guitar strings are made out of steel, which rusts readily and plating doesn't adhere as well to flexible materials like wires.
You use an acid flux to remove the oxidation on aluminum. Guess what your sweat will do if it is acidic enough? Hobo soldering tip 101 - no flux, use your sweat if you can get away with sodium in your solder and your solder has no flux.
I destroy guitar strings on a near-weekly basis, despite all the anti-corrosion plating tech they have.