[GordMay]

What are you trying to clean off the Aluminum Water Tank?

Aluminum reacts with air to grow its own oxide coating very fast. This hard, dark gray coating protects the metal. It''s found on all bare aluminum surfaces, including Water Tanks, which, if rubbed, leaves a dark gray mark. If washed off the of the metal, it quickly forms again. It presents no majorhealth hazrd, if left un-disturbed.

There are five categories of aluminum cleaners:

1. Mild Soaps and Non-etching Detergents: Non-ionic detergent such as "Joy"
a. If a mild soap or detergent is gentle enough o be applied with bare hands, it can be safely used on aluminum without spot testing first.
b. Automatic dishwasher detergents should be always spot tested first. Some of these detergents can discolor non-finished and anodized aluminum and can even bleach painted aluminum.
c. Non-etching cleaners are acidic or alkaline solutions containing inhibitors that permit the cleaning of the metal without etching. Care should be exercised in their use.

2. Solvent and Emulsion Cleaners:
a. These cleaners are relatively mild solutions which can be used for removing dirt and stains that cannot be removed by milder cleaners.
b. They generally can be used on bare, anodized, conversion coatings, and porcelain finished aluminum without spot tests, but product directions should always be followed exactly.

3. Abrasive Cleaners:
a. These include polishes, cleaners, cleaner polishes, wax cleaners, scouring powders, metal brighteners that contain abrasive particles, and may also include water, oil, wax, silicones, soap, acids or alkali.
b. These cleaners depend on vigorous rubbing action along with a chemical reaction, and can remove most dirt, stains, and corrosion products from aluminum and will restore most weathered aluminum surfaces.
c. They are rated as moderate and heavy-duty. Abrasive cleaners also include etching cleaners, and special heavy-duty cleaners.
d. Household cleaners with coarse abrasives should ONLY be used on aluminum with PORCELAIN FINISHES. Even a very fine abrasive can dull or scratch a highly polished aluminum finish. Fine pumice powder and stainless steel wool (grades 0000 to 00) can be used with these cleaners, but regular steel wool may leave rust stains.

4. Etching Cleaners: Try "AC-266" (Sherwin-Williams), or "Van Glo" (BASF-Wyandotte Corporation)

5. Special Duty Cleaners: Try "Sure Klean Aluminum Cleaner" (ProSoCo, Inc.).
a. These cleaners should remove aluminum oxidation, atmospheric dirt and carbon, and other surface stains from all types of aluminum surfaces.
b. Domestic soap flakes
c. Acrylate emulsion polish

From Alconox: http://metal-cleaning.alconox.com/cleaning_aluminum.htm

Alconox®
Concentrated, anionic detergent for manual and ultrasonic cleaning. Free rinsing to give you reliable results without interfering residues. Ideal for cleaning contaminants from glassware, metals, plastic, ceramic, porcelain, rubber and fiberglass. Excellent replacement for corrosive acids and hazardous solvents. USDA authorized. Dilute 1:100. pH 9.5

Liquinox®
Concentrated, anionic liquid detergent for manual and ultrasonic cleaning. Free rinsing to yield reliable results with no interfering residues. Extremely mild and completely soluble in hard and soft water. USDA authorized. Dilute 1:100. pH 8.5

Citranox®
Phosphate free, concentrated cleaner and metal brightener for high performance removal of metal oxides, scale, salts and inorganic residues in manual and ultrasonic cleaning. Corrosion inhibited and free rinsing for reliable results and no interfering residues. Ideal for trace metal analysis. USDA authorized. Dilute 2:100. pH 2.5

LUMINOX ®
A low foaming, neutral pH detergent for use in manual, ultrasonic, and machine cleaning. This safe-handling detergent can be used for non-corrosive cleaning without chelation or alkalinity waste treatment problems. Recommended for cleaning aluminum and soft metal, alkaline sensitive labware, and medical instruments in aluminum trays. Luminox is free rinsing to eliminate interfering residues.

HTH
Gord