Advice in terms of windows and doors maintenance.
Both systems should be cleaned with water and soap with a neutral pH, and a sponge or soft cloth. Avoid solvents and substances with abrasive properties. Use lubricants to keep mechanisms (locks, latches, …) in a proper condition. Maintenance frequency largely depends on building location. It is sufficient to conduct it once or twice a year in rural areas. It should be conducted more often in an industrial environment or a coastal zone to avoid the deposition of saltpetre or other corrosive substances.