I'm sorry Spunky is having a problem with her ear. That's no fun at all!
First things first -- the best thing you can do for Spunky is to make her an appointment with her veterinarian. The issue you're describing does not read like ear mites and, as was previously stated, the majority of indoor, well-cared for cats will not contract mites. But, that being said, it does seem as though Spunky may be dealing with an ear infection. Ear infections can be caused by an overgrowth of yeast or by bacteria. But, regardless of the cause, an infection would require a trip to the vet as untreated ear infections can lead to a host of other problems. And, I'm sharing this not to scare you, but in older cats, tumors of the ear canal can be an issue. A foul odor coming from the ear is always a cause for concern and it would be in Spunky's best interest to be seen by her veterinarian as soon as possible (it's not an emergency, but she should be seen sooner rather than later).
In the meantime, since you're not reporting seeing debris or wax in her ear, do not try to put any kind of liquid or cleaner in her ear. The vet will likely check Spunky over and, depending on what they see when examining the ear, may do an ear swab and/or culture. Once a diagnosis is made, a treatment plan should be discussed and decided upon. It all sounds scarier than it is, but I do hope you'll get Spunky to the vet and, when you can, update us on how she's doing. Good luck and please keep us posted.
And, before I go, here are some vibes for you and your kitty