A healthy cat who grooms herself should smell like almost nothing, so a musty odour that hangs in her fur deserves a proper trace rather than a scented wipe. Grooming spreads saliva over the coat, but it does not remove oil, shed undercoat, or moisture trapped close to the skin, and it cannot fix a smell whose source is actually her ears, her mouth, or the bed she sleeps in. Work through the likely sources one at a time, changing one thing and then smelling again a few days later, so you learn which fix actually cleared it.
Smell the coat zone by zone before you wash anything
Get your nose close in a few places: behind the ears, along the middle of the back, at the base of the tail, and on her chest. A musty, old-blanket smell concentrated along the back and tail base often means sebum and loose undercoat have built up faster than her tongue can clear them, especially in longhaired or older cats who cannot twist as well as they once did. A smell that is strongest around the head points elsewhere — ears or mouth — because she grooms her face with a paw after every meal and transfers that odour onto her fur. Checking bedding, a favourite cardboard box, and any damp corner she naps in matters too, since a mildewed sleeping spot will re-scent a clean cat within a day.
Brush out the undercoat before reaching for a bath
For most musty coats the first fix is mechanical, not wet. Brush her in short sessions with a tool suited to her coat length, working out the soft, dull undercoat that traps moisture and odour against the skin. Pay attention to the trousers on the back legs, the ruff, and the belly fringe if she allows it, where shed fur packs down unnoticed. Wipe her afterwards with a plain damp cloth to lift loosened dander rather than using fragranced sprays or powders, which sit on top of the smell and can irritate skin or put her off grooming the area. Reserve a full bath for a cat who is genuinely greasy or has rolled in something, using a cat-safe shampoo only, because over-bathing strips the coat and can make oil production and odour worse.
Check ears, mouth, and skin for the real source
If brushing and clean bedding do not shift the smell, look closer. Ears with a yeasty, musty odour, dark debris, or a lot of scratching need a vet's eyes rather than home cleaning fluid poured in blindly. Bad breath from dental disease or sore gums can perfume the whole coat of a cat who washes her face constantly, so note drooling, dropped food, or a preference for chewing on one side. Part the fur in the smelliest area and look at the skin itself: redness, flaking, crusts, bald thinning, or a greasy feel under your fingers all suggest the skin, not the fur, is generating the smell, and that pattern needs veterinary input rather than more grooming.
When the musty smell is a vet problem, not a grooming problem
Book an appointment if the odour returns within days of a thorough brush-out, keeps getting stronger, or arrives alongside weight change, increased thirst, reduced grooming, or over-grooming one spot raw. A cat who stops washing properly often does so because of pain, nausea, or difficulty reaching, and the smell is then the symptom you noticed first. Take a note of where the smell is strongest and what you have already tried, because that narrows the vet's search considerably. Keeping a simple dated log of brush-outs, bedding washes, and how quickly the smell came back in KinsLe using Care Teams turns a vague 'she smells again' into a pattern a vet can actually work from.