The finish is the result of a chemical etching process.
After the castings are chemically "washed" using hot sodium hydroxide, and "ph" neutralized by boiling in distilled water; they are "cold dipped" into the zinc chromate solution. This is a combination of nitric acid, sulfuric acid, and chromic acid.
Chromic acid is a known carcinogen, and as such, the sale of this item is closely regulated (IT IS ALSO DANGEROUS!!!).
We send ours to a metal laundry company. This is one facet of restoration best left to the professionals. Even a small company such as ours which specializes in carburetor restoration cannot justify the waste water treatment facility necessary to obtain the regulatory licenses; NOR DO I WISH TO DO SO.
For the hobbyist, the best method of regaining the factory finish is not to lose it. Cleaning of the carburetor in clean gasoline, with a toothbrush may be more labor intensive than using carburetor cleaning (lacquer thinner, in a well-ventilated area, may also be used); but these solvents will not remove the greenish-gold original finish.
There are also some paints out there that are quite useful if you plan to offer the carburetor on Ebay, but do nothing to protect the metal.
Jon.
