I was steaming milk when a burly man in hi-vis took the lid off his keep cup and uncovered a thriving colony of mould. The sides were bearable—the ceramic walls had a thin film of dried milk—but lying at the bottom was what looked and smelt like blue cheese. Not edible blue cheese. More like the forgotten piece of glad-wrapped vintage cheddar at the back of the fridge, behind the out-of-date jam.

“You may have to give it a bit of a rinse,” the man said.

A bit of a rinse, I thought. I’m no Shannon Lush, but the cup seemed to need more of a twenty-four-hour soaking in industrial bleach. How long had the bacteria been breeding for? 2 weeks? 4?

The man then dumped $4.50 on the bench and sat down. The coffee was $4.30 because we rewarded customers who used keep cups by shaving 20 cents off the normal price, but I decided to pocket the change—out of resentment and as a cleaning fee.

—

I’ve gone through phases of being precious about cleanliness. As a child, I was terrified of germs. At school, I’d wash the cut carrots and celery sticks under the drinking fountain as an extra act of caution just in case mum had dug up the veggies from our garden and used her usual cleaning technique of whacking the compost-covered spinach against the countertop a few times, the same way you might dust off a welcome mat.

I wasn’t being overly paranoid, either. Once I bit into a ham and salad sandwich and, upon inspecting its contents, noticed half a slug squirming on a cucumber. The other half turned out to be what I thought was an extra juicy cherry tomato in my mouth, the ones that squirt when you bite down.

By the time I was older, though, germs were less of a threat. I lived weeks at a time in a hippy van, walked around uni with no shoes and at Little Creatures during a lecture break would often salvage the remains of an abandoned plate of chips.

During this time I bought a keep cup. And I got into a bad habit of never washing it, sometimes because there was no cleaning facility handy but mainly because I was lazy and insouciant. So what if it’s a bit dirty? It’s not going to kill me, I thought.

After a particularly long time without washing the cup, I strolled barefoot into a cafe in Fremantle and plonked the cup before the barista. The inside wasn’t mouldy or anything, but when I took the lid off, the barista scowled.

“You may have to give it a bit of a rinse,” I said.

But he didn’t. He didn’t on purpose and the scowl turned into a sly grin when I took the first sip and realised the coffee had an off-taste, a taste that only can be achieved by leaving leftover milk in a hot car for three days.

I felt unfairly punished as if I’d urinated on the carpet and my owner was rubbing my nose into the wet patch. In a way, though, I respected the barista’s standpoint. He wasn’t paid to scrub my cup. And by not cleaning it, I learnt a valuable lesson.

—

As a barista, I always clean a dirty keep cup. Cafe protocol doesn’t permit otherwise. But after trying to scrape the mould off the hi-vis man’s cup, using a knife as a chisel and the palm of my hand as a hammer, I gave up. The wait on coffee was already too long and I couldn’t hold my breath for any longer, I reasoned.

“Just chuck the espresso in,” I said to the other barista.

“What, just on top of that?” he pointed to the cheddar-like mould.

“Yep,” I said.

“Surely not. That’s a pretty bold Occ Health and Safety breach.”

Ignoring the barista, I poured a double espresso and milk into the cup, the solid chunks still clumped together at the bottom. Almost like a dirty keep version of a Trumpet icecream. I popped the lid on.

“Thanks, mate,” the hi-vis man said as he collected the coffee. And I too had a sly grin, imagining the man learning his lesson.