Rust on tow ball

chris640

Drove down to Pembrokeshire Sunday with my new tow ball and Alko stabiliser,tow ball was cleaned with emery cloth and brake cleaner before leaving,now 4 days later  it is covered in light rust,should I remove with a cloth or sand it off with emery cloth
again.

If i had put the tow ball cover on would that stop the rust?last stabiliser was a blade type and ball was always smeared in grease,so no rust.

Chris