How cold is too cold?

what is washer fluid: water soap and methyl hydrate (methanol).
it is cheaper and more effective to use the ingredient that keeps the mix from freezing than paying for a dilluted mix.
add methyl hydrate to your regular mix. it evaporates quickly so don’t leave the mix open and be prepared to add more the colder it is. add straight methyl hydrate to your detail rag.

from titan labs:

Glass Gleam products don’t provide freeze protection. To reduce the freezing point of water to 0°F (-18°C) it is necessary that methanol be added to the water so the mixture is about 28% methanol and 72% water. For protection to -20°F (-29°C) you need 36% methanol and 64% water

also search the videos “weather or not”