When I waxed the camper this past fall, it seemed like maybe it was the first time it had ever been waxed by hand--there was a lot of random adhesive/calk globbed on in places that it shouldn't have been, and the black streaks were pretty bad. I used Meguire's One Step RV Cleaner Wax, #50, and it worked well on everything--streaks, adhesive, bugs, etc. Then I put clothespins on the ends of my gutters so that water runs off them and not down the sides. That has greatly reduced the streaking so far. Good luck!
2015 XLR Hyperlite 30HFS5 (mods being performed regularly)
2009 Salem LA 292fkds (gone)
Nights- ('12)23 ('13)23 ('14)15 ('15)31 ('16)25
2014 Harley Davidson FLHX (XLR cargo)
2014 VW Jetta TDI (diesel sipper, camping support vehicle)
2011 Ram 2500 CC 4X4 CTD, B&W Companion (toy hauler hauler)