Published: January 4, 2018
Q. I work at a museum and my current project is to remove both oxidation of copper and what I assume are residues from calcareous water from a valuable, antique sink. From the XRF-analysis, I have identified the sink as having a copper base with a zinc-nickel plating. My primary concern is that I need to preserve the “used” and dull appearance on the sink and not achieve a shiny, “like new” result.
It came to my attention that your products are safe to use in the food industry, which made me think they must be gentle, non toxic, and not leave any residue. Is this correct? It is important that there will be no detergent residue remaining on the sink because we don’t want any reactions with the metals later over time.
A. You are exactly right. All of our detergents are quite safe, free-rinsing, biodegradable and several are indeed used in the food industry, including both detergents I recommend here.
We recommend starting with a 0.5% solution of Alconox® Powdered Precision Cleaner. Begin with spot testing in an area that is not readily visible to be sure the results are as you’d like. If you don’t get good enough results, and need a stronger detergent, we would then recommend 0.5% of Citranox® Liquid Acid Cleaner and Detergent. Normally, we would recommend the opposite order of detergents which to try. Citranox cleaner is fantastic at brightening soft metals, like copper. This is of course precisely what we are trying to avoid.
Monitor closely and rinse thoroughly and promptly in both cases. In the case of Alconox detergent, so that you remove the oxidation and calcium without darkening. In the case of the Citranox solution, so that it doesn’t remove too much and brighten the object.
Both purchased products will come in handy for future restoration projects. Alconox powder is an excellent general cleaner and Citranox detergent excels and brightening of metals and removing inorganics. Furthermore, our detergents have been used with antique and art restoration for decades.
Always happy to discuss further at any time!
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