Or “maybe”. I’ve never tried it, but read an article on the process many years ago. The writer sprayed water with a bottle sprayer, which allowed him to shape the sawdust into hills and dips. You have to allow time for it to dry out after play, of course, if you want to store it.
Another step is to dye some of the sawdust for sprinkling on the surface — the article’s author bagged it with some Rit Dye. You can see how long ago this was — I believe it may have been in the old (American) Wargamer’s Digest.
Anyway, it sounded like a good way to make a storable sand table. I just never got around to it.
One example I did see in action: this fellow sprayed the surface with green spray paint. I don’t know what happened after the game; I assume he lifted the hard surface off and threw it away. Rather wasteful, I’d think.
Plus, this was at a convention; other attendees were less than pleased.