Quoting Lori Woodel
Amazing! How do you keep them from getting dusty? Have you ever built a Lego train track that is suspended from a ceiling?
To answer your question, it's getting dusty and i use a paintbrush to undust the lego. And when it's very dusty then i put the lego model in the disheswashmachine. The model will come out as new. And no, i did never build a traintrack on the ceiling. Perhaps i will some day..... Good idea.