2.0 Grinding outer shell and structure
WARNING: This page is about a different car, the 2011 BMW 750xi, 2011 BMW 750Lxi, 2010 BMW 750xi, and 2010 BMW 750Lxi. However, it is still accessible from the selected car via links, so may be relevant.
Do not use any abrasives (grinding wheels, paper, etc.) which contain iron (risk of corrosion).
Always replace abrasives which have already been used to treat steel (risk of corrosion).
Use stainless steel wire brushes only (risk of corrosion).
Reduce speed of grinding machines. Excessive speeds cause a smearing effect.
Do not use coarse abrasive grains (only ≥. 80).
Do not grind notches into the material (risk of cracking).
Do not grind the material thin.