clicliclic said:
what is the active ingredient for the removal of oxide and sulfide
layers that is found in standard contact cleaning sprays? If you put
some spray some onto white paper it will leave oily stains of a
reddish color.
Fifty years ago such an orange or red oily liquid used to be available
in small bottles, and just a small droplet was applied to a contact to
be cleaned.
Something of this sort is still available. It used to be called by
the brand name of Cramolin (I believe this was made in Germany), and
the Caig Laboratories company now makes a similar product under the
brand name of DeOxIt.
Is the active ingredient an organic liquid of red color, or perhaps a
solid red chemical dissolved in an organic solvent? What is its name
or chemical formula?
The MSDS (Material Safety Data Sheets) I've looked at for the Caig
products are somewhat unrevealing. The active ingredients are
proprietary / trade secret and are not specifically described.
According to one USENET posting I've seen in rec.antiques.radio+phono,
it is possible that one of the active ingredients is oleic acid. "As
to the anti-oxidant qualities of Oleic acid, it has been used for
years in metal-finishing as a cleaner. It is the active ingredient in
well-known brass-clock cleaning compounds (though "tempered" with
acetone), and in several other similar applications."
Another posting states that
As Peter pointed out (which I had forgotten), oleic acid is the main
ingredient in clock-cleaning formulas that have been in use for a
very long time. Since acetone doesn't dissolve oxides, that pretty
much leaves the oleic acid as the active ingredient.
I've been curious for years about Cramolin's (DeOxit's) composition.
The MSDS doesn't list it, but somewhere years ago I read that it was
oleic acid. And I found a 1930 trademark registration for the
original German product, under the name Gramolin, described as a
treatment for motor commutators. It's not much of a stretch to get
"Gramolin" from "Gramme" (DC machines were sometimes referred to as
Gramme machines) and "olin" from "olein," some of the derivatives of
oleic acid.
http://www.ibiblio.org/herbmed/eclectic/kings/acidum-olei.html gives a
description of oleic acid, and mentions that in the (impure) form in
which it's often manufactured it's a dark, reddish-yellow or
brownish-red oil. Once fully purified it's colorless.
So, it would not be surprising if the sprays to which you are
referring are a mixture of somewhat-purified oleic acid, with solvents
(e.g. various alcohols) and propellants (propane and/or carbon
dioxide).