The one mistake: paper towels
Paper towels shed fibers and push dirty water around. A microfiber cloth for edges + a proper squeegee for the glass is non-negotiable.
The pro soap recipe
One drop of dish soap per gallon of water. One drop. Most homeowners use 10× too much, which leaves residue. Filtered water is better — Chicago tap is mineral-heavy.
The squeegee angle
Start at the top corner. Tilt the squeegee so only the leading edge touches the glass at ~15°. Pull in one continuous S-motion. Wipe the blade on a clean cloth after every pass.
Order of operations
- Brush or vacuum loose dirt off the frame.
- Apply soapy water with a sponge or microfiber.
- Squeegee from top corner, overlapping each pass by 1 inch.
- Wipe the frame and sill with a dry microfiber — never the glass.
When a pro is worth it
A professional does a typical Chicago home (24 windows inside + out) in ~90 minutes with zero streaks. DIY on the same house is half a Saturday and you still have the exterior of the second floor. Our rate for 16-24 windows inside & out: $195.