Finn tells Han that he worked in "Sanitation" on Starkiller.
FINN
The flooding tunnels are over that
ridge. We'll get in that way.
HAN
What was your job when you were based
here?
FINN
Sanitation.
HAN
Sanitation? Then how do you know
how to disable the shields?
FINN
I don't. I'm just here to get Rey
It just occurs to me - the "I was in sanitation" line given to Han seems to be the only actual canon evidence of "Sanitation" job.
But was it the truth"?!?!
Finn is always trying to create a positive impression of himself with the Resistance, from the get-go:
He tells Poe that he's rescuing him because that's the "Right thing to do" (with Poe quickly seeing through the fib: "You need a pilot!")
He tells Rey that he's Resistance (she buys that because she's a romantic 19 year old still playing with X-Wing pilot helmet)
He tells Han that he's Resistance (that one lasts about a minute - Han was not a romantic 19 year old even at 19 :)
In reality, we know that he was 1% of his class, model stormtrooper cadet, personally groomed for promotion by Captain Phasma (Evidence of that: #1; Evidence #2).
However, I am pretty sure telling Han "Hey, I was 1% of my class, model stormtrooper cadet, groomed for promotion by Captain Phasma" isn't high on his list of brand management plans.
Far better to pretend to be a lowly "sanitation" worker than top-flight cadet that he really was.
So, my question is - do we have any direct canon evidence proving that the "sanitation" job was real and not a fib to make himself look better to Han/Resistance?
Knowing where trash compactor was isn't direct evidence, though it is circumstantial one.