I got a hold of so,e original DZUS EHF6-60 fasteners for my car. Anyone know the best way to clean them up? Also are the ‘keys’ or fasteners that were used on cars like 1075 fabricated and bonded to the fasteners or were they readily available? Looks like the normal slot but with a square in the middle. I saw other posts where other were fabricating them themselves. I could use those measurements to cut some out of stainless or aluminum?