I get the call from CleanSafe at 11am on a Tuesday. The firm's blokes have turned up at a house expecting to do a routine spruce, only to discover that its late resident had fallen behind with the cleaning. Thirty years behind. This is one job for which my university education may come in handy. Not so much what I studied, more the experience of living with Dirty Penny, a girl whose feet you could smell on the carpet even when she'd been out all morning. My mate bought her Fiat Uno for £20 and found a flotilla of fag butts in a tar puddle in the driver's door.
That wouldn't trouble CleanSafe's founder, Steve Broughton. On the drive to the job he treats me to the highlights of his gruesome back catalogue: from mopping up a bloody double suicide attempt in an Asda toilet, to cleaning the flat of a crack-addict schoolteacher, which included a room full of sex toys and fried chicken boxes.
As boss of a company that works with the police, local councils and mental health trusts, Steve has spent more time than most 'slipping around in people's bodily fluids'. Slit wrists, bloody mattresses and maggots are par for the course. 'If people are moaning about problems at work or not being able to afford a holiday,' he says, 'send them to me for 10 minutes.'
I'm hardly enthused when we pull up in a quiet street in Carlsharlton, Surrey and enter a dilapidated semi. Yellow nicotine-stained paper peels off the walls, and there's an unholy smell rising from the bare floorboards. 'You should have been here three months ago,' says the executor of the will, a long-haired neighbour whose chain smoking suggests he'll be happy to see the last of the place.
He shares the details. Neighbours had spotted the woman's curtains left open and called the police, who entered through an upstairs window - into a room full of dog excrement. The uniformed horde then stomped down the stairs, only to find her sitting in the living room, puffing away on a fag in her armchair. A paramedic examined her. 'You're having a heart attack,' he told her. 'Are you surprised?' she replied.
She passed away four days later. Which is where it gets grisly. The executors found that every room had been stuffed so full of junk that they couldn't open the doors. They were getting bitten by the fleas that had colonised the carpet; the dog had been shut in one room for months. There were other finds: a 1920s fox-fur stole, live ammunition for a.303 rifle, and a newspaper from 1918 announcing that World War I was over.
'All the problem jobs come from hoarders,' says Nick, Steve's right-hand man, as he kits me out in a protective romper suit and gloves. 'If you know anyone who has started to hoard, stop them now.' Later, spraying cleaning fluid on the living-room doorframe, he warns against the dangers of smoking. The brown sludge from decades of 60-a-day slides down the woodwork.
My beat is the kitchen. On the floor, I find a yellowed page of the Daily Mirror featuring Bryan Robson, Man United's Captain Marvel. It's from 1987. Elsewhere, a page featuring Roger Daltry is imprinted on the floorboards. Nick hands me cleaning fluid: 'Just spray, spray, spray. Then bust your balls and get it off.'
I start on the cupboard under the sink, the inside of which looks like the target of a dirt protest. One shelf takes about 25 minutes. After an hour and a half I stand back to admire my work - one cupboard cleaned, one house to go.
Steve tells me that many of his team take a perverse enjoyment in the work. And it's not just the pay, which at up to £26k a year is decent for the cleaning industry. He reckons there's a sense of completion in returning hideous places to their original state.
As I contort myself to reach the dark corners under the sink, my face is far too close to the grime to share that. While I'd love to leave something inspirational, my gift to the world will more likely be an inch of sludge on the hinge of a kitchen cupboard.
I open a drawer and discover 10 unopened packets of Marigolds. The old dear was clearly stocking up on cleaning products, while shutting her door to the mess. In public, I'm told, her hair and make-up were always immaculate.
By late afternoon, sweat is running down my forehead. This scrubbing is hot work. But I feel myself getting drawn in: soon, I'm urging myself to get the cupboard done so I can start sweeping that floor. Steve was right. Pride gets you in the end.