Derek Cheung, 23, spends his free time at shopping malls and food courts. But not to shop or eat.
Cheung is a volunteer with the Restroom Association of Singapore (RAS) and conducts random spot checks at toilets to ensure the standards of cleanliness are maintained.
The Restroom Association of Singapore is a non-profit organisation founded by a man proudly known as 'Mr Toilet', Jack Sim, in 1998.
A video published by the Singapore Kindness Movement on Monday (March 25) follows Cheung as he takes time after work to conduct his checks.
He says in it: "My friends know that I actively volunteer, but when they find out that I conduct public restroom checks, they are quite surprised."
We think surprise is an understatement.
Cheung shared that it was his National Service (NS) stint cleaning toilets that made him aware of the "bad habits" he and his unit mates had formed, and that inspired him to volunteer his time for this special cause.
So what's on his checklist when he does his toilet patrol?
A clean entryway and working taps are what Cheung looks out for first.
Next, strong hand dryers are a must to keep the floor clean because users will "flick less water".
Finally, in the cubicle itself, he checks that the toilet paper dispensers are replenished, the flushing system and locks are working, and the toilet bowls are clean, taking note of stains and odour.
It's not the most glamorous job, but Cheung is passionate about keeping Singapore's public restrooms clean.
In 2016, when he was still in NS, Cheung was recognised for being a 'star volunteer', leading "mystery audits at more than 30 MRT stations, shopping centres and office buildings". That number has definitely grown.
Cheung has conducted more than 100 public toilet checks in the past five years.
And the young man has wise words to share:
"I see it quite simply, if we wouldn't dirty our own homes, we shouldn't do it outside. People are less likely to keep the toilets clean when they see that the toilet is already dirty."
In the same vein, can we also just put it out there that toilet seats are meant to be sat on, not squatted over. If everyone did so, there wouldn't be dirty toilet seats. Simple, right?
In the Facebook video's comments section, many can't believe Cheung's dedication.
Wrote commenter Le Xuan: "Wtf this is next level nice."
While others want to be his best friend (in NS).
And then there's this recommendation: