Two scrubbers are better than one
Use two different scrubbers—one for inside and one for outside—so you don't carry pollutants and bird excrement inside.
Liquid dish detergent rules
Any kitchen dish liquid cleans dirt and grease and leaves the glass slippery so your squeegee glides well. A 100-percent biodegradable soap will protect sensitive plants outside. Inside it will protect toddlers and pets who put their mouth on the windows or sills.
Vinegar works, too
If you prefer to use natural cleaning products, vinegar is a viable choice for cleaning windows. Vinegar (acetic acid) cuts grease and doesn't streak which makes it ideal for cleaning glass. We recommend a solution of 50 percent white vinegar and 50 percent tap water.