Dust in My Zen Garden

What do you suppose it means that dust has collected on the surface of my desktop Zen Garden? Even the rake has a layer of dust on it.

This can’t be good. I’m thinking it speaks to the lack of attention I’ve given to my personal Zen during the past several weeks. Months?

In my defense I was “out” for nearly a month due to my own clumsy nature & the resulting injury and no one was tending my “garden” while I was gone. Still…there is a pretty obvious layer of dust on the surface of the sand, the rocks and the frame in which the garden resides. Sigh.

How does one “dust” sand? I think I can fix the state of the rocks and the rake fairly easily but I am completely unsure of how to remedy the situation with the sand.

Google is no help. I suppose I will just have to figure it out on my own. Perhaps this will be an exercise in "restoring my Zen".