If plain water doesn t work try it with a product called krud kutter.
Clean black streaks off gutters.
5 steps to brighten gutters.
Simple green any oxygen bleach whitewall tire cleaner alumklean by wsi or a mixture of 1 3 cup of a strong household detergent and 2 3 cup of tsp cleaner.
Use this solvent to scrub off the outer surface of your gutters with a stiff brush or a piece of cloth.
Krud kutter 32 oz.
The black streaks are a result of electrostatic bonding of tar asphalt from roofing material and other debris to aluminum metal material.
Streak getter will break down this bond which will allow you to remove the unwanted streaks off your aluminum gutter with little effort no scrubbing.
As you work take care to stay away from trees and power lines and have someone steady your ladder.
Depending on the heat type of vegetation and rain accumulation some plants and grass will take differently to degreasers.
Rain carries them down the sides of the gutters where they stain the aluminum.
One of brands gutter zap has a great history of cleaning gutters and is biodegradable.
You can try a variety of products but success depends on your geographic area.
Even for vinyl gutters liquid detergent alone cannot be used to clean the gutters properly.
Here are some products to try.
Ready to use formula makes cleaning gutters easy with a simple spray on wipe off application.
If you have a pressure washer try washing them off.
Gutter cleaner removes black streaks dirt mildew stains and more.
For that mix half cup of household liquid detergent with a half cup of bleach in two gallons of water.
When you are doing regular gutter cleaning you may notice unattractive streaks in and around your gutters these streaks are usually either rust mold or simple discoloration it is easy to get rid of those ugly stains.