A simple sash or stop repair can often restore a window to good working order. If a sash is temporarily stuck because of high humidity, a change of weather may correct the problem. If a sash moves reluctantly, clean the sash channels.

Windows that have been painted shut require a little more effort but can be opened, too.

If windows stick, chisel any dirt or large globs of paint from the channels, and then sand the channels smooth with sandpaper wrapped around a wood block. It also helps to coat the surfaces of the channels with wax so the sash will move easily.

If the window binds against the channel, widen the channel by inserting a wood block inside the channel at the point that binds and tapping it with a hammer.