pipedown wrote:

wrote in message
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Does anybody know how to remove rust stains from asphalt shingles? I
have to vents that have left rust streaks running all the way down the
roof to the gutters. I have light gray shingles.


Stop the source of the rust perhaps by painting or replacing the nails (with
copper) and the stains will fade in a year or two. The rust stain is just
particles trapped on the shingle surface not actual rusting of the shingle
so a rust cleaner like CLR will have limited effect (except by virtue of the
soap it also contains). Plain old dish soap and a garden hose would be how
I would start. Don't spray too hard or the grit will come off too much and
you'll wish you had left it alone.


You can remove the rust stains easily with oxalic acid. But, first you
must eliminte the source of the rust or they will re-occur.