uPVC windows are a low-maintenance product that are easy to clean. The best way to clean a uPVC window is to open it as far as possible and remove any built-up dirt by vacuuming in every alcove - if your vacuum cleaner has a soft brush nozzle, use it to minimise the risk of scratching. Use a bucket of warm soapy water and a soft cloth to wipe down the window. avoid scouring pads as this would remove the glossy finish. You can remove the excess water to prevent streaking using a clean cloth, a chamois or a squeegee.