My indoor cat's fur smells like smoke and we don't smoke!

I noticed today that my 10 year old cats fur smells like smoke around her neck. Neither my husband or I smoke and she is an indoor cat. I don't ever have candles in the home either so it can't be from that. Could it mean there is something wrong with her? Maybe something with her skin or something with her mouth that is transferring to her fur? I've noticed a couple of times her fur hasn't smelled nice and 'cat like' recently but this is the first time I have noticed the smoke smell. Another thought is it could be left over from the spot on we gave her but that was two weeks ago, we have used it before and I have never noticed it before. I don't want to call the vet if this is a waste of time

That is strange. What does her breath smell like and does she have tartar or bad teeth? Could it be from that and left over smelly saliva from grooming herself?

I will check her breath when I get home but it's normally fishy from her food! I can't really check her teeth as she is a pain when it comes to checking her mouth!

Cat’s coat may contain mats that are wet and stinky.

You may ask some other person to smell the cat - smell depends on the person.

Note that infections cause bad smells, but from the smell alone one cannot identify the infection. 

Exactly how "fishy"? If you can smell it when her mouth is closed then there might be something going on inside her. Ckd can cause this as can oral infections.

You say smoke? Could it be wet dog type smell? If so she may be drooling or possibly have a bladder infection causing her to "leak".

Other thing that can cause smells is anal gland problems. Does she cry when using the toilet? Does she drag her butt on the ground after going?