They are discolored with vertical gray streaks on the sides, and gray spots on the bottom where water flowing down the sides accumulate in "puddles" along the bottom outside corner.
I've tried the following, applied with a saturated paper towel to small test areas:
-- full-strength bleach
-- full-strength Simple Green
-- full-strength white vinegar
-- full-strength TSP substitute
-- 91% rubbing alcohol. Some improvement, but labor intensive to do all
158 feet.-- paint thinner
I've also tried the following:
-- spray gas log cleaner
-- spray Fantastic
-- a mix of bleach with Oxydol laundry detergent, applied with brush. Makes some improvement.
-- a mix of 1 part Simple Green, 1 part bleach, 2 parts water, applied with a sponge. Makes some improvement.
I haven't tried ammonia, since I don't have any in the house.
I admit that I haven't had the patience to wait 5 to 10 minutes for any of the above to work. I was hoping to find something that I could apply with a dust-pan brush and have the streaks magically disappear immediately. Any suggestions?
Thanks,
Ray