Window sashes should be lubricated on a yearly basis. Lubricating the sash prevents squeaking and sticking and also protects the window from freezing shut completely. Using a regular bar of body soap as a lubricant is more economical and less messy than oils or sprays. A finishing coat of silicon spray can be applied after the soap to ensure smooth movement of the window. The solid oils and waxes in the soap, however, are enough to keep the window operating properly.
Open up the window as far as it can go.
Inspect the window track for any rough edges. Use sandpaper to smooth out any rough patches you may find.
Wipe down the window track with a wet towel and then rub a bar of regular body soap up and down the entire track. Close the window and then open it again. Continue this process until the window slides up and down easily.
Spray the tracks with a silicon spray for additional protection. Slide the window up and down a few times after applying the spray so the silicone gets into all of the cracks and crevices.