Best Way to Remove Matts From Fur

This post is about Callie, one of my rescues. When I got her and her mother Missy, they were both horribly matted. They had been neglected and abused so after I clipped them out of both kitties with buzzers, I figured I wouldn't have to worry about their coat anymore. Well, here it is late spring/early summer, exactly one year from when I got them, and while Missy's coat is still beautiful and tangle-free, Callie's matts are back. They are not as bad as they were last time, but they are there all the same.

So before anyone says this, I do get now that at least with Callie, it's partly a seasonal thing and she will need to be brushed regularly around springtime. I've slacked on that for 2 reasons: 1) I've had numerous long-haired cats that have never been brushed in their lives and didn't have this issue, so I mistakenly assumed that Callie was the same and 2) Even if I had known that Callie needed to be brushed, she is still very skittish and has a tendency to get extremely violent when she feels threatened, and I can just tell that brushing her is going to be a struggle.

The only things I can think of are to brush them out, which will be painful for her, and like I said, a major struggle that will be made even worse by the fact that it hurts her, or to shave them out like I did last time, but that's a struggle as well and I'd prefer not have to do that if it isn't necessary. When Missy had her matts, I gave her a bath before I brushed her and that seemed to loosen up the tangles (though I still wound up having to shave to worst ones), but bathing is not an option in Callie's case.

I should stress that this cat is the most violent cat I've ever encountered. She's gotten much better but at the same time I've also been very careful not to do anything that might upset her and cause the violence. I am still quite afraid of her when she gets like that.

So does anyone know any tricks for removing matts from fur, maybe something you can put in them to loosen the tangles? I'm looking for something as quick and painless as possible, to minimize the stress on both of us. I don't know if anything like this exists, but if it does someone on here has got to know about it.

TIA

I can handle her some. She will not tolerate being picked up and DOES NOT like having anything but her head and back touched, and the mats are on her side, low down toward her belly, so it's going to be difficult anyway. The position you speak of, I use often with my other cats for clipping claws and giving medicine, but I'm afraid that would simply terrify Callie. She was abused and does not like being approached from behind. When I shaved her last spring it took 3 people, one for her front paws, one for her back, then me with the clippers, and we had to cover her head with a blanket so she couldn't see (or bite, since the lucky person with the front end got bitten numerous times) and to muffle the sound of the clippers. And she still fought like a rabid animal the entire time. If I take her to a groomer or vet she will definitely have to be sedated, and will probably still manage to cause major harm to someone before they can even do that. I've had stitches 3 times because of her and I'm the only person she even mildly tolerates. I'd rather go it myself at home. I think I will try after I type this, even if I can only do one mat at a time. I'll do 2 or 3 a day until they're gone. I will get the baby brush and do what you recommended afterward. And what kind of fish oil should I purchase for her, I'm assuming I can't just break open the fish oil pills made for humans. Thanks for all the advice, I'll let you know how this goes.