Room smells stale

Sorry your kindness has resulted in your room smelling unpleasant. Have you tried lighting some candles in there.
The smell could be on the walls and paintwork so if you can you could try cleaning those.
Essential oils on cotton wool dotted round the room may help too.

How about some incense sticks?

How kind 💕

I'd suggest that the mattress might be worth changing to start with.
Also your cleaner might not have penetrated the carpet deeply enough, especially if you lift it and find the floorboards are stained.

Without being too offensive, have you tried getting down and close to the carpet, mattress, curtains etc and had a really good sniff of everything to see if you can isolate the source of the offending smells?

Well done for housing the young family. A friend's daughter did the same and they had a few problems as well.

Firstly, I would check the closets and the chest of draws ..
These can be cleaned with a touch of vinegar and baking soda to eliminate odors - and is commonly used for refrigerators. The main supermarkets worldwide, sell a liquid cleaner with these ingredients.

If the room is carpeted, I would have it professionally cleaned.

I would look under the bed of course and see if anything could be activating this awful aroma.

I would go to the nearest Hardware Retailer and ask what product (s) would be best to clean the walls and not destroy the paint.

Also the wet nappies from the toddler: This is similar to a male cat "spraying" .. Not easy to remove, however, the hardware retailer should be able to help you.

Good luck.

Incense sticks - patchouli is the best . It will get rid of any unpleasant odour

A sprinkle (or deluge!) of bicarbonate of soda gently brushed in and left for an hour or so will should freshen up carpets.
What a simply wonderful thing you have done for this poor family x

I think it's the walls -
I'd probably use a bleach solution on one morning and leave the windows open and doors closed.

I have found this problem occasionally when working in a hostel where residents tended to stay in one room.

Bleach walls, wash curtains and carpets and then reevaluate.

You could also have a professional out to clean the mattress if it's a quality one.

Good luck.

Any product such as shake and vac will just mask the smell.
You need to absorb the smell into bicarbonate of soda, coffee grounds, oats or vinegar.
Fresh air in the room needs to circulate so a through draught will help.
If you haven’t already then wash all curtains, mattress protectors etc.
Once the room is a little fresher then use a fragranced product.

Buy a large quantity of soda bicarb and spirit vinegar on line.

Sprinkle the mattress liberally with the soda and leave for 24 to 48 hours then hoover off. Same with the carpet. Mix soda plus vinegar plus washing up liquid and use to wash down the paintwork. Lots of youtube videos will tell you the quantities. Spring and warmer weather coming so the windows can be left open. Wash the curtains if washable. I expect it will gradually fade. And it may just be a different human smell as you say.
What a kind gesture to house them.

A dehumidified will deff help , I had damp wood smell couldn’t get rid of it, bought de humidifier from Argos , run it off n on for a week , left it running a couple of nights , it not only collected excess moisture but it took away the damp smell, I have not used it for many months now, the smell has not come back. It was about £145 a challenge make( other makes are available) .

You could also try sugar soap for all the paintwork..

I would definitely get rid of the mattress and wash the curtains if you've not already done so.

When I was wee, my mother would put a bowl of (uncooked!) porridge oats in seldom used bedrooms for a couple of days to freshen them up for guests! She said the oats soaked up the stale smells.

I think you probably need to redecorate and replace the soft furnishings.
It was good of you to take the family in but they've left now.

NotSpaghetti

I think it's the walls -
I'd probably use a bleach solution on one morning and leave the windows open and doors closed.

I have found this problem occasionally when working in a hostel where residents tended to stay in one room.

Bleach walls, wash curtains and carpets and then reevaluate.

You could also have a professional out to clean the mattress if it's a quality one.

Good luck.

I agree, I work in a care home and walls are regularly cleaned and also repainted, makes a big difference.
Carpets can be cleaned and curtains washed.

When we had Indian family stay in one of our holiday cottages the smell of curry was overpowering. I read somewhere to put vinegar in a pan of water and boil it for several hours it worked. I then tried it on one occasion I left chicken wings I was boiling for stock boil dry to the point the kitchen was full of smoke and everything was coated in grease It still smelled after I had washed everything in cupboards walls floors curtain. Etc. the boiling vinegar worked but it took several goes. It’s cheap even if it doesn’t work for you
🤞

Get one of those things from Dusk where you burn essential oils . That’s what I do after ourvpussy cats have had ‘accidents’ and the smell remains after cleaning up. I choose nice flavours to burn but my favourite is sandalwood.

I think the smell will just disperse with time. Wear perfume yourself so you don't notice it so much. Air the room and busy yourself with other things. In the cold weather just leave the door open into the rest of the house. I have noticed a different smell after visitors have stayed too .

I would have the carpets and curtains professionally cleaned. We had problems with an elderly cat and carpet cleaners didn't work, but a professional one guaranteed to get rid of all smells, and he was right.
An sad downside to a charitable act.

I've had this problem with soft furnishings due to my father being stuck in the same room for seven years and his being incontinent .

I grow lavender in the garden and I sprinkle the flowers onto the carpet prior to vacuuming .
I also have filled a spray bottle with
lavender water ( from Amazon ) and spray freely .

I have a really keen sense of smell and often feel sick if I sit next to someone smelly on the bus , but this system works for me .

I would wash or get dry cleaned, all soft furnishings, curtains,,bed covers, cushions, wash and replace pad.

Get the carpet professionally cleaned.

have you moved bed around to see if 'anything' left under it. and check for stains on mattress.

The nose doesn’t lie and you can’t unsmell it. You may have to get the whole room and furnishings professionally cleaned.

I scrub all walls and floors with strong vinegar water regularly. I sprinkle huge quantities of soda on rugs, leave as long as I like, then hoover well.