Help me unravel this mystery before I burn the contents of this room down

Oh I should also add: are the curtains new? I had a set of blackout curtains from Dunelm which genuinely made the room reek of feet. I blamed our visitors (I'd bought the curtains just before they came to stay) but eventually figured out it was the curtains.

I left them up for a month and they never aired out, it was just a constant stench. Thankfully they took them back!

Vampire? 🤔🧛‍♂️

This won't help now but, the only success I've had combating feet/shoe smell was with the charcoal-based Odour Eater insoles. I'm just putting it out there in case anyone reading wanted a tip.

Most sprays just seem to cover the smell, and not very well.

I thought for sure this was going to be a situation where the carpet would need cleaning, but since I've seen you say there is no carpet, I'm absolutely mystified, sorry!

Regarding ozone machines, US government guidelines say they are potentially unsafe and can trigger respiratory illness.

I second an ozone machine. You can get one for about £70 on Amazon. They actually neutralise the source of the smell, not just cover it up.

I'd be throwing out all of the linens and the mattress, and the blind. It's not fair to the next lodger to have to sleep on them, apart from the smell.

Ventilation is obviously key, but, as @RhubarbGingerJam suggests, have you tried an air purifier? I find mine very effective in removing strong cooking smells, and the fumes from next door's woodburner. A couple of powerful ones left in the room overnight when windows are closed might help.

When the windows are open, try positioning an electric fan pointing out of the window to force the smell out.

When all that's done, perhaps you should send him a bill for everything you've had to throw out.

Getting a distinct H P Lovecraft vibe from this thread.

p.s. Dead mice totally do stink. Only for a few days, as their small bodies dry up quite quickly, but it's funky while it lasts.

Was he vaping in the room without your knowledge. I had (briefly) a lodger who did this, and didn't work it out until after she'd left. The smell of her vapes and her disgusting scent combined and even now, two years after she went, the room she was in still smells different from the rest of the house.

I would wait until we get reliably dry weather and put the mattress outside for a week or so, covered in an old sheet in case of bird splats.

Have you tried sprinkling Cat Litter on floor and bed etc? You leave it for a few days - it is messy though.

This could be it! They've brought some sort of experiment home and not told you. Ask them.

@NotAgainWilson massive sympathies to you and may your haz mat suit stay strong.

we’ve had some right horrors stay in flat and holiday homes we used to have.

first suggestions are - strip the room of all fabrics, remove (and dispose of if it smells at all) the mattress protectors.

basically leave the furniture you can’t remove in and that’s it.

then air the room constantly for a week. Leave the ensuite bathroom door ajar (if the bathroom is en-suite).

if the things you have removed don’t smell after a week - then we can eliminate any fabric things being an issue.

Do you have a garage or something the desk etc could go in for the purgatory session? Can it be dismantled and disinfected in case the smell is sticking to the underside of it?

Can you ask the lodger what his condition was as you are struggling to sort out the room. Yes it may upset him but so does foot rot stench infection to lovely room hosts. I’m sure there is a softer way to word it…

Did he walk around bare foot or in socks?

Have you tried bicarbonate of soda ?

This can be used for neutralising fridge smells.

Get some, and spread it out over a large tray to get a big surface area to absorb the dodgey vapour.

Alternatively go full on NBC and get some activated charcoal.

The sweet smell is probably related to general body odour and it has probably permeated the mattress. I have had similar with a relative staying in my spare room. It only eventually went with airing for AGES. Like weeks.

I think we need a pic of the fluff @NotAgainWilson

Does it smell?

Oh yes they do!

That's how we discovered what Dcat had hidden under the piano.

I don't think that's true. We had a horrible smell in our kitchen coming from the brickwork. Husband removed a few and found a decomposing mouse. The stench was truly horrendous🤮🤮🤮

Throw out all the bedding and the armchair, as well as the roller blind.

Spray pet urine enzyme spray all over the mattress and let it soak in.

Get the floorboards redone. Get the walls and ceiling repainted, also the radiator, and the door.

Sorry @NotAgainWilson but the "burnt sugarfeet stench" made me snort and scared my cat!

The fluff everywhere - do you think a bird could have got in and flapped about? Or a squirrel - they can be really stinky.

Maybe you will have to bin everything and redecorate. There's definitely something strange responsible.

I'm afraid I would have to throw the bed out, along with any other soft furnishings.

Invested now… @NotAgainWilson I need to know if you’ve taken the radiator off?!

Either you're exaggerating or you have some kind of smell-related hallucination going on because it's very extreme for a smell to be around a week when the source has been removed. And you don't have carpets so it can't be in that. If you've changed the bedding it literally can't be possible.

The only similar thing I can think of is when we moved into a house with a weird smell and it turned out to be the curtains because the previous owners had smoked weed in there on a regular basis, but even that wasn't a strong smell (especially considering how strong and nasty the smell of weed is even in passing), and he can't have been rubbing his feet on the curtains.

Rats/mice - same smell when rotting rodent.

I rented a room on a regular basis to the grandson of one of DM's friends (family friend) and I rented another room to friend of DB who came down to London a lot filming. First man was here a year, second person here same year but on and off in months but fairly regular for about a year. After both rooms were vacated there was a smell. It turned out one of them had been bringing things home to eat (sausage rolls, mini sausages, crisps) even though I said, please don't do this as this attracts mice (thank god I had/have a good cat).

After they both left (all above board), it was similar, lots of strange smells, dust/lint and I had to completely deep clean both rooms (I was having no lodgers), got Airwick ball with odor eating gel in it and replaced both mattresses and actually replaced carpets (they needed it anyway as they were both old).