I will give this tip only once. Add half a cup of household bleach to 25 liters of pure and use a back pack/trolly on first cleans a see your window shine and sparkle. Then clean/ rinse with pure. I have heard so many windies ask what they can use on really badly soiled window and feel pure will not do the . Its the bleach in so many cleaners like Virosol that does the cleaning. Don`t use this mix if your water goes through a R.O. before the pole. Warning, remember this will damage clothes so be careful and don't breath in . And to all the negative ones that will knock this , do some research.