How do you clean the dark mildews off concrete walkways? I think the mildew build up is a result of using calcium salt in winters. I know I can use bleach but I'm afraid bleach will also kill the grass on either sides of the walkways.
#2
RatRacer
3500 psi pressure washer w/ 15° fan tip is what I use.
Try mixing a weak solution of houshold bleach and water in a 5 gal plastic bucket (1 cup/gal). Use a bristle brush. You can make a stiff one by cutting off the straw on an old broom below the stiching. Dip and agitate. You should see the mildew loosen. Water grass before if you are worried about kill. This works as well as the $10/gal stuff.
I've used this technique several times over the years, works great. The only difference is I have a rotary tip that spins a pencil tip in a circular motion.