Agree with the above on documenting.
If you want to try a home remedy less severe than buffing or claying try a little goof off on the edge of the streak.
It has taken all sorts of stuff off my cars and won't harm the paint.
2011 535i Black Sapphire Metallic, Sport, Euro Del (ret)
2009 328i Black Sapphire Metallic
2007 Honda S2000 Berlina Black