We advise that you clean all products with hot soapy water. You should avoid using harsh chemicals, especially on woodgrain or painted products. On our uPVC sliding sash windows, you can use a silicone spray to lubricate the moving parts such as the springs. Do NOT use WD40! Please head to our blog to read our guide on how to clean s ash windows. The material used for the seals on our uPVC casement windows and doors, and uPVC flush casement windows and doors is TPE (thermoplastic elastomer). In order to maintain the flexibility and the lifespan, we recommend to treat the seals annually with silicone spray or talcum powder to rub. They may not come in contact with concentrated detergents or similar products. If your windows and/or doors feel like they are “sticking”, it may be time to tend to the seals.