Like putting on cologne or perfume and failing to mask body odour. You have to actually clean, not spray carcinogenic scents on the mess that briefly mask it. It’s usually fabric like bed sheets and couches, carpeted surfaces, human/animal dander and oils. Garbage cans with poor seals. Poor choices in cat litter systems. Stuff like that.

Then open windows for air circulation. If you can set your furnace fan (if you have one) to always run even when not heating that also helps redistribute stale air.

Beyond that just give up and go nose blind.

Edit: ceiling fans are great too.