dust in the mouth

[frindle]

Hello.
I can guesss what the underlined phrase means, but I'm not sure.
Would you please tell me what it means exactly?
Thank you.

Paul's family did not own land. He was paid for his work,
but everyone knew that money was nothing but dust in the mouth.

 

[konungursvia]

It means something ephemeral, temporal, worldly, and ultimately without value.

 

[frindle]

Thank you^^