I have been using this simple and inexpensive solution to clean my windows and mirrors and it leaves them streak free!!!
A 1 gallon bucket
Ammonia (mine came from Dollar Tree)
1 Table spoon
Squeegee (mine came from IKEA)
Put 2 tablespoons of Ammonia into the 1 gallon bucket bucket.
Fill the 1 gallon bucket with water all the way up.
(If you need less – then 1 tablespoon Ammonia with 1/2 bucket water).