This time of year, in between storms, approaching mud season requires a lot of windshield wiper fluid. Sometimes, I can find it for a little over a $1 a gallon and when I do, I stock up on it. But, recently, Jon stopped to get some that he desperately needed and it was $3.79 a gallon!
I found a homemade recipe with stuff that I have on hand (and can easily replenish) so when we finish an old bottle I will just fill it up with the following:
1 Gallon (less 3/4 cup) of water (just eyeball it)
1 T dish soap (whatever you have on hand Palmolive, etc)
1/2 cup ammonia
few drops food coloring (not required, but it serves as a quick reminder and warning if you keep it blue or you could just write with a marker on the bottle)
Recap the bottle and gently shake.