corrosion from blue -20F washer fluid

[RICE RACING]

Can not comment on 'pre made' stuff.....

I make my own WM50 *by weight*
Methanol (racing from 44gal drum)
Water (rain water) out in country, not shit from a town water supply etc.
Never ever any deposits, evaporates clean, stays in suspension and totally clear (batch done for ~ 6 years) as a test.

I would never 'trust' something pre made as you don't know what grades of products they are using to make the concoction.

p.s. white residue is typically calcium, lime, flouride etc put into town water supplies.