Washing windows is a rite of spring and one where the effort pays off immediately. Finally, you can look past winter’s grunge and see the plants poking through in the garden. That is if you learn how to clean the windows without leaving unsightly streaks and smudges behind. Here’s some tips on window cleaning from the experts at Consumer Reports who contributed to, “How to Clean Practically Everything.”

Start with the window frames. Clean very dirty frames before you start your window cleaning. Vacuum the runners of aluminum window frames and doors, then polish the frames with silicone car polish, which can also be used in channels to help windows slide smoothly. Or lightly oil the channels. Wash painted or vinyl frames with a sponge dipped in warm water and detergent. Rinse with warm, clean water, and towel dry, if necessary.

Then the panes. How often the outsides of windows need cleaning depends on where you live, but the insides usually need cleaning twice a year. Wash windows on a cloudy day or when the windows are in shade, because direct sun will cause streaking. If your home has many windows, divide the window cleaning job into segments rather than attempting to clean them all in one day.

Your supplies. You’ll need two buckets; a sponge; a good-quality rubber squeegee; a clean, lint-free cloth; a chamois cloth; and a commercial cleaning solution or your own. Take down your curtains—it’s a good time to clean them—or loop them over a hanger, out of the way. Clean windows from the top down. Use a slightly dampened sponge to apply the window cleaning solution. Wipe across the window with dampened squeegee blade, then wipe the blade. Follow with a rinse of clean water applied with chamois. Polish off any remaining moisture with the dry cloth.

If you’re painting. Remove new paint spatters with a cloth dipped in water or glass cleaner (for water-based paint) or turpentine (for oil-based paint). Use a single-edged razor to scrape old paint, holding it at an angle to avoid scratching the glass. Leave 1⁄16 inch of paint on the edge of the glass to protect the frame from condensation inside and rain outside. Note that glass cleaner can soften water-based paint. If you spray it onto a painted surface, blot, don’t rub; the paint will harden once dry. Wipe away putty marks with ammonia.

Special windows. Clean small windows or stained-glass windows with a damp sponge first, then wipe with a clean, damp chamois. Polish with a clean cloth. Treat delicate stained glass with care. Painted glass should be gently cleaned with a damp chamois. Most new double-hung windows have tilting sashes, a handy feature that lets you pivot them inward for easier cleaning. With most, you simply flip a lever to tilt the sash in. But with some, you must pull the sash out of the track.

Skylights. Some high windows and skylights can be cleaned with special extension tools, but it may be practical to hire a professional window cleaner, if only for the out-of-reach windows.

Window-Cleaning Warning

In Consumer Reports' window tests, one surprising discovery was that it’s easy to stain some models if you use the wrong cleaner. Ammonia-based formulas, including some Windex products, can cause streaks or film on windows. So before you grab your squeegee, check the manufacturer’s website for instructions. And whichever cleaner you use, pick a cloudy day for window cleaning—sunlight can make a cleaning solution evaporate before you finish—and clean from the top down to prevent drips.

Smart Cleaning Tips