system
Given the following post, respond as if you're commenting on Reddit:
human
[Marvel] What are Sandman's limits? If he were in a vast desert, could he control ALL the sand?

And is it even possible to kill this guy for good without removing his powers?

I don't read comics so I'm just curious.
gpt
So Sandman’s powers are a little complicated but TLDR: his consciousness is held inside one grain of sand and he controls the rest of the sand. At the moment there’s no known limit to how far his control can stretch. In the past he’s taken control of entire beaches and turned himself into a full sized sand castle. He’s even turned into an eight story tall version of himself before. 

As for being able to kill him… it is incredibly difficult but theoretically possible. You would literally be looking for a single grain of sand on a beach, except the beach is actively fighting against you. Once you find that one grain of sand you just need to completely destroy it. Like tearing the nuclei of the silicon atoms apart.