Tiger stripes, those dark vertical stripes that appear on aluminum rain gutters. Customers sometimes call us about these dark stipes that will not wash off. The first assumption is that the paint has gone bad. This is usually not the case.

Naturally, pollution and dirt build up on the top lip of the gutter. When moisture combines with these pollutants, it streams down the face of the gutter. Future precipitation will continuously follow the same path. Over time, the buildup becomes alternating light and dark stripes

Rain gutters require regular maintenance to prevent the normal buildup of soil deposits and oxide accumulations. The level of maintenance depends solely on the atmospheric conditions in a geographic region.


Simple cleaning procedures should be preformed to reduce the buildup of these deposits. Tiger stripes imply an already heavy buildup on the gutters and will require a strong cleaning solution.

Instructions...The following simple cleaning procedure should be preformed at least once a year or more often if necessary.

General cleaning...For surface soil and stains, such as those resulting from industrial fallout, tree sap, insecticides or chimney fumes, use ordinary nonabrasive household detergent like  or . The solution should be applied to the soiled surfaceby means of a soft rag, sponge, or soft bristle brush with a gentle rubbing action. Do not rub vigorously so as to create glossy areas over the satin finish. Soft bristle brushes equiped with a long extension handle may be used to reach some of the higher areas. It is important that immediately following all washing operations, the entire surface be thoroughly rinsed with water.

Stubborn stains...If stubborn stains are encountered, use a heavy duty cleaner such as . Heavy soil deposits may not be removable in one application and may require repeated cleaning over some length of time. Do not use cleaners containing abrasive particals, ammonia, solvents or paint removers for cleaning. These materials may soften or remove the finish.

Climatic Problems...Climates vary considerably from one locality to the next. In some areas, mildew may be a problem. It appears as black spots on the surface and is usually detected first on the underside of the gutter. For removal, prepare the solution below and apply as outlined above.

1/3 cup detergent ( for example)

2/3 cup 

NOTE: Sodium phosphate (TSP) is a cleaning agent, food additive, stain remover and degreaser. It is a white, granular or crystalline solid, highly soluble in water producing an alkaline solution. Most often found in white powder form, it can also be called trisodium orthophosphate or just plain sodium phosphate. Trisodium phosphate was at one time extensively used in formulations for a wide variety of consumer grade soaps and detergents, but ecological problems have largely ended that practice, at least in the western world. Substitutes are not as effective, but the raw chemical can be bought in bulk.

1 quart 5% Sodium Hypochlorate solution  for example

3 quarts water

WARNING...The above products can cause severe eye damage and can burn unprotected skin.  Always wear gloves, suitable clothing and eye protection.

CAUTION: Greater concentrations may cause damage to the finish.

Mix up the gutter cleaning solution and clean the gutters along one side of the house at a time. Mix the cleaner in a five gallon pail and apply with a soft brush. You can use an extendable gutter cleaning pole so you don't have to climb a ladder. Take your time and brush slowly, permit the cleaner to stand for only a couple of minutes then wash it off. Be sure to hose them off entirely and don't let the cleaners run down the vinyl siding.

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