There was an article on the old 'Transformer Variants' site that from memory suggested the only way to avoid chrome wear was to keep your Transformers in a sealed vacuum.

The same thing happened to my Soundwave, Sideswipes feet, and Grimlocks tail. They are all my originals and very carefully played with when I was younger. For approx. 5 years they have been locked away in my glass display however there has been noticeable chrome wear developing.

It's not only the G1's though - my MP05 is also showing signs of chrome wear and it was literally taken out of the box and placed into a cabinet without even transforming him once.

This is just one of the pitfalls of a G1 collector. You have to learn to accept it otherwise it'll just drive you insane.