The best solution is a drybox; a sealed filament container, usually with some desiccant inside. But in a pinch, [Spacefan]’s quick and dirty $0 drybox solution is at least inspiring in terms of ...

and the small-scale test with the RS1 showed that with a full filament spool in the box, humidity inside the container would only drop very gradually as more and more moisture replaced what was ...