Both BMW and Mercedes stress that anything that sticks to the paint surface, like dead bugs, tree sap, or bird droppings, should be removed immediately. Because rubbing aggressively can ruin the matte finish, the companies recommend dousing the item in insect remover or car-wash soap before gently rubbing it away. The key, Pennington says, is to avoid excessive friction when trying to remove anything stuck to the paint surface. Water spots should likewise be cleaned off quickly, even if they result from something as trivial as driving past a garden sprinkler.
As waxes and polishes are verboten, Pennington advises adding some UV protection and shine to matte paint with specially formulated spray waxes. Meguiar's own Ultimate Quick Wax, for instance, doesn't have any harsh cleaners that will damage matte paints, and it creates a protective coating over the paint surface.