Cleaning Stucco with Copper Gutters

I’m cleaning a stucco house later today that has copper gutters and downspouts. It’s a high dollar property, my inclination is to not use HW mix on the walls. Thanks for any suggestions.

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I think I remember a thread where @Harold dealt with some copper gutters so I’ll tag him.


I’ve used a mix of salt and vinegar to clean copper guidon spearheads when I was in CAV.
But it involves scrubbing.

Theses guys have it down pat but dont list what they are using. Got to be some kind of acid.

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I didn’t explain this well. I don’t want to do anything to disturb the patina. Thanks

You seen that ad Plastic makes it possible?

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I never had a problem with stucco and copper. It’s roof mix that you have to worry about. Stucco I’m usually at about 2% and spray it on stucco and copper gutters. Dwell and rinse as normal. Anything much stronger I would be more cautious.

Edit: this is only with pre existing patina present. Never ran into fresh copper.

@marinegrunt you’re memory impresses


Geesh, don’t give him props ,his heads big enough already


I got my mix on a copper railing cap and it turned green.

My bad, misunderstood what you were after.

How strong was the mix? Did it dry?

Walk away. Never clean something you can’t replace. Patina takes time and gives it an Aged look . You can’t replace that. SH will remove that in seconds. Then turn it green .
Don’t make there problem yours.

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Please inform my wife. She’ll tell you I’m always wrong and am just not remembering it correctly. (even though she’s the one who doesn’t remember :grin:) Just don’t ask me what I had for supper yesterday.


@Harold I didn’t prewet it. I noticed it 10 minutes after I sprayed it. I prewet the rest and made sure it I didn’t, spray it directly and I only let the railings dwell for 5 mins and the rest of the caps were fine.


I ended up pre-wetting the copper avoided it as best I could and then had my helper immediately rinse the downspouts and gutters. No problems when I left yesterday and I haven’t gotten a hysterical phone call today so I think I’m good. As always thanks for the input.


I’m not a PW guy, but if you ever accidentally remove patina, you can put it back on (somewhat, probably not exact). Only reason I know is that I saw a program about installing new copper roofs and adding a patina for character, found it fascinating. I find it even more fascinating that you could accidentally remove it, but then kinda put it back on. From this site:


The hot boiled egg method is perfect for creating a brownish patina on copper. Eggs are hard boiled and then crushed to pieces in a re-sealable plastic bag or container while they are still hot. The copper is then placed into the bag and sealed for minutes to hours, depending on the desired shade of brown patina. The longer the incubation time, the darker the brown color. This method is ideal for small copper items, but large ones are difficult to manage through this technique.


Miracle-Gro plant fertilizer is an excellent oxidizer of copper. For a blue patina, mix one part Miracle-Gro with three parts water for a solution that you can spray or wipe onto the copper. For a green patina, mix one part Miracle-Gro with three parts red wine vinegar. A patina will form within 30 minutes and become permanent within 24 hours.


Soaking copper in white vinegar and salt will create a blue or green patina. Other ways of doing this are to bury the copper in sawdust or crushed potato chips soaked in white vinegar. The longer the copper is buried, the darker the patina becomes.

edit: I’m not saying that these techniques would be viable for 100’ section, but if there was a bit of damage I would think I would give it a try.