I've found that "streaks" are made up of dirt and grime that a wash & wash compound will not dissolve. What works great for removing them is LA's Totally Awesome Cleaner. Available at Amazon and Walmart. Make sure you follow the instructions on the bottle.
'04 K3500 Silverado LS with LS3 Connect & Cruise- with Intimidator SSI PKG- Reprogrammed 4L80E
2016 Salem 27RKSS
1984 CHEV SCOTTSDALE K20 2GCGK24J0E1XXXXXX (Chevrolet Legends-Class of 2019)
"...exhaust fluid? We don't need no stinkin' exhaust fluid"