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
Dual-purpose paint can opener
New blade = no streaks
A 12- to 14-in. squeegee is a good size for most situations. Put in a new rubber blade after each cleaning to prevent streaks.
New blade = no scratches
A razor blade removes paint overspray and gunk. Keep the glass wet and use a new blade each time. Microscopic rust particles on the blade can scratch the glass.
Details matter
Carry two detailing rags—one for dirty jobs like sills and the other for detailing the edges of the glass.