Gutter Brightening in Charlotte
What tiger striping is
Those vertical dark streaks on the face of a gutter are not general dirt. They are a bonded film of oxidised finish and airborne residue, laid down by water running repeatedly over the same points of the front edge. That is why a house wash leaves them behind.
The staining is a symptom
Water should leave through the outlet, not over the front lip. Heavy striping usually means the run has been overflowing - from debris, from lost fall, or from being undersized for the roof feeding it. Brightening the face without asking why treats the mark rather than the cause.
What brightening can and cannot do
It removes the bonded film and returns the finish close to its original tone. It cannot restore a finish that has chalked through, and on a badly weathered run replacement is the more honest answer.
Why the streaks are vertical and evenly spaced
The pattern is not random and it is worth reading. Striping appears where water has repeatedly gone over the front lip at the same points, and on most houses those points are fixed - the low spot in a run that has lost its fall, the section furthest from the outlet, or the length directly beneath a valley that concentrates roof flow. So a run with striping at one end and a clean face at the other is telling you where the water is failing to reach the outlet. A run striped evenly along its whole length usually means it has been overwhelmed rather than blocked - too much roof feeding too little gutter.
The order of operations that saves money
Brightening a run and then correcting the overflow means paying for the same face twice, because the mark returns as soon as water goes over the lip again. The sequence that works is to fix the cause first - clear the trough and the outlet, correct the fall, resize or add a downspout if the arithmetic says the run is undersized - and then brighten. At that point the finish stays clean, because nothing is running over it. We will say when a run is not worth brightening. On aluminium that has chalked through, the coating is gone rather than dirty, and no amount of cleaning brings it back.
What the process involves
A brightening treatment is chemical rather than mechanical: a cleaner formulated for the oxidised film, dwell time, and a controlled rinse. Pressure is deliberately kept low, because the finish underneath is thin and forcing the issue removes more than the stain. It is worth pairing with a clean rather than booking separately - the trough is open, the outlets are being checked anyway, and the fall can be assessed while someone is already at the run.