# How do I clean a copper roof?

**URL:** <https://boards.straightdope.com/t/how-do-i-clean-a-copper-roof/366968>\
**Category:** Factual Questions\
**Created:** [August 2, 2006, 3:13am UTC](https://boards.straightdope.com/t/how-do-i-clean-a-copper-roof/366968 "2006-08-02T03:13:49Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![purple\_haze](https://avatars.discourse-cdn.com/v4/letter/p/db5fbb/32.png) [@purple\_haze](https://boards.straightdope.com/u/purple_haze)\
**Post date:** [August 2, 2006, 3:13am UTC](https://boards.straightdope.com/t/how-do-i-clean-a-copper-roof/366968/1 "2006-08-02T03:13:49Z")

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We have a copper roof on top of the bay window on our house, and I want to restore it to it’s original lustre. Does anyone know of a product I can use? Also, once I do clean it I’ll need to seal it against weathering again.

I’ve checked Google and the yellow pages, gone to Home Depot and Lowe’s, etc. No dice. The only copper cleaner I can find comes in small bottles. How far does that stuff go? I don’t think it’s intended for cleaning a roof.

Anybody know?

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**Author:** ![What\_Exit](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/what_exit/32/10652_2.png) [@What\_Exit](https://boards.straightdope.com/u/What_Exit)\
**Post date:** [August 2, 2006, 3:30am UTC](https://boards.straightdope.com/t/how-do-i-clean-a-copper-roof/366968/2 "2006-08-02T03:30:49Z")

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The Copper Oxide build-up actually protects the copper roof. It is not normally recommended to remove the Copper Oxide.  
[This might help a little, best source I could find for a cite](http://www.copper.org/applications/architecture/arch_dhb/finishes/finishes.html):

> [@](#):
>
> Copper and its principal architectural alloys are relatively active metals which, when left unprotected, tend to oxidize. Long term atmospheric exposure in other than arid climates **generally results in the formation of the naturally protective gray-green patina**.
> 
> Because copper and its alloys afford a broad spectrum of both natural and weathered colors, much effort is expended to either hasten the natural weathering by chemical means or to preserve the bright natural colors through the application of clear protective coatings.
> 
> This section presents extensive reference data on the subjects of natural weathering, chemical coloring, clear organic coatings and opaque coatings both organic and inorganic. In addition, information is presented on the advantages and potential pitfalls of oiling, waxing and lead coating.

[If you still want to clean it, read this article.](http://www.copper.org/resources/properties/protection/green.html#cleaning)

Jim {My bolding above}

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**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\
**Post date:** [August 2, 2006, 3:32am UTC](https://boards.straightdope.com/t/how-do-i-clean-a-copper-roof/366968/3 "2006-08-02T03:32:53Z")

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[http://www.copper.org/](http://www.copper.org/) looks to have about everything you could want to know about copper.  
From a search of that site: [Rehabilitation of Copper](http://www.copper.org/applications/architecture/arch_dhb/copper_alloys/rehab.html)

> [@](#):
>
> To clean unevenly patinated copper:
> 
> 1. Sponge bathe copper with a mixture of six parts concentrated phosphoric acid to one part concentrated nitric acid diluted by no less than 50 percent distilled water to a pH between 1 and 1.5. A thickening agent can be added to the acid as a buffer and to contain the acid and make its removal and disposal easier.
> 
> 2. Leave the acid solution on the copper for one minute, then life off with sponges soaked in sodium bicarbonate solution. Neutralize any residual asid by rinsing the copper with fresh water and treating with a sodium bicarbonate paste at pH 10, rubbed on with sponges and flushed off with water.
> 
> continues…

Dig some more, that quote was the first likely hit I saw in a site search for ‘cleaning roofs’.

Once you’ve got it clean, there are several products like [this](http://www.finishing.com/Chemicals/everbrite.shtml) you can use to protect the shine.

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**Author:** ![purple\_haze](https://avatars.discourse-cdn.com/v4/letter/p/db5fbb/32.png) [@purple\_haze](https://boards.straightdope.com/u/purple_haze)\
**Post date:** [August 2, 2006, 3:46am UTC](https://boards.straightdope.com/t/how-do-i-clean-a-copper-roof/366968/4 "2006-08-02T03:46:56Z")

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Thanks for the quick replies! (Rolls up sleeves)