Actually, it will depend on what activity the vehicle is performing. Has it been in the field, running cross-country, sitting in a motor pool, or is it a derelict wreck? Additionally, what environment is involved? Tracks have become a pet peeve of mine after 38 years in the Army/Army Reserve with about half on and around tracked AFVs. I apologize, ahead of time for the rather wordy response.
1 - With a few exceptions, tracks are made out of a manganese/steel alloy and as such they rust. However, when operated in their natural environment, the soil will polish the metal components. Here is