make salt rust fire extinguishers shut

[Frank_Stein]

Alternate suggestion 1: Scuffing salt lines. Spacemen passing over salt disturb the line, or have a chance to break it at least. Make an unbroken line be required to actually trigger wraith corporeality (ie, a salt tile requires two adjacent tiles to also be salty to be effective) so that stray single tiles don't catch the wraith out.

This. It's just loose salt on the ground. Walking over it should spread it around and break it up.