Takes the fog out of your bones

[Angie8]

What does "takes the fog out of your bones" mean?
This is a sentence from the fiction I'm reading, "The Chee Chalker" by L. RON HUBBARD.
Below is the relevant paragraph:

Sven watched Danton climb into his black slicker and leave.
“Give him a drink, Morris,” said Chief Danton, picking up his uniform cap.
“Something up?” said the barkeeper.
“Naw. Just a body down at Tamgas.”
“Who is it?” said Morris the barkeeper, blowing his nose on his apron.
“I dunno,” said Danton.
Morris set up a drink of rotgut. “Takes the fog out of your bones,” said Sven apologetically as he drained the glass.
“Who found it?” said Morris, faintly interested.
​

I guess it might mean "to warm you up," but it would be weird to be said by Sven in this situation. Sven said that to Morris, or was he just talking to himself?

 

[probus]

As far as I can determine, that is the only time the phrase has ever been used in English. Therefore nobody knows for sure what dear old L. RON meant.

 

[Charlie Bernstein]

Yes, you're reading it right, Angie: to warm you up and to wake you up. To make you alert and help you focus. To cure your sluggishness. Some people call a slug of booze an eye-opener.