If you haven t cleaned the debris out of your gutter yet do this first with a garden trowel.
How to remove stains from white gutters.
Water based formula can also be used on mobile homes rv s and campers to remove black streaks and other stains.
Wet the gutter with a garden hose after pre wetting the area.
Simple ready to use formula.
Set up a ladder at one end of the gutter and fascia where the black streaks are located.
Dip your scrub brush in this solution and scrub off the stains.
This is a product that will remove them with remarkable ease.
Rust residue dirt buildup and corrosion can all be removed by scrubbing the gutters clean.
I assume from what you have described it is a white gutter with aluminum oxidation on it.
Apply product allow to penetrate for 2 minutes and wipe or rinse clean.
You just spray it on let sit for a few moments and then wipe it off with a damp clean cloth or rinse with clean water.
Your gutter will look as good as new.
Removes tough outside stains like mold mildew oxidation tree sap and bird droppings.
Dip a nylon scrubbing brush into the soapy water.
Apply the chemical according to the manufacturer s instructions.
Reposition the ladder when necessary to reach all parts of the gutter and fascia.
Rinse with water and if necessary reapply the chemical to remaining stains and brush again.
It is actually pretty easy with the right material.
Brush the gutter with a stiff bristle brush.
This bleach mixture will also kill any mold or mildew that s growing on your gutters.
Try spraying an all purpose cleaner on the stains and scrub them off with a scrub brush.
These may require you to vigorously scrub or make take several attempts but it can all be removed.
On stubborn streaks let the chemical dwell longer being careful not to let it dry.
I clean this for customers all the time and the product to use is called gutter zap.
Climb up the ladder and spray the black streaks with gutter cleaner.
Using a power washer clean your gutters to get the initial mildew and grime off.
If it is mold it will come of very easily with bleach.