It's a dirty job is a paper note in Fallout 76.
Location
The note is found in Wavy Willard's Water Park. It is on top of a cabinet in the mechanical room of the wave pool.
Transcript
Larry,
Hey, guess who Supervisor Jenkins picked to clean the toilets again? If you guessed it was you, then ding, ding, ding - you win a prize!
Oh, and it's Chili Cookoff Week, so you better stock up on cleaning chemicals. I put a whole bunch of them in the utility tunnel under the entrance to Crocolossus Mountain.
Reggie