Copper on roof?

[A-OK Pressure]

I have a slate roof to clean. The ridges have tarnished copper on them.
I'm going to be cleaning it with SH and water per the recommendation of some members on this board and I'm rinsing it after.
I was wonder if the SH will effect the copper in any way?

 

[carolinawildcat]

I'd be careful using sH. If you have copper flashing that can't be seen, such as on the high side of chimney or skylight, no issue. If the copper is decorative in addition to being functional, ie in valleys of shingle roof, you could have a big problem with streaking & spotting. Test in an inconspicuous area first if possible. I learned the hard way that copper corrosion not only looks bad, but its expensive to replace. I have had mixed results with heavy patina, sometimes no issue, sometimes spotting.

When all else fails, rinse before, during and after.