If you are in a pinch and don't have soda or peroxide around your house, you can squirt some window cleaner onto the fabric.
Working with ladders is dangerous so maybe you can get your window cleaner on the job !
While you can use straight vinegar and water to clean windows, adding a few simple ingredients to your homemade window cleaner will make it even more effective.
Mix one part window cleaner or liquid dishwashing soap to four parts water.
If you notice a stain in between cleanings, spot treat it by spraying window cleaner directly on the affected area and gently wiping it with asoft cloth. You can also rub each slat with a dryer sheet after each cleaning.