old cat w/ sore paws from unclean toileting

My elderly (18years) cat has slowly become less active over the last year or two. This is starting to present a few health problems for her.
As we have been living in the same place for years nows, I think the places that she is toileting are becoming full with faeces. This leaves badly smelling dirt in and around her claws. With her advancing age she is grooming less and her claws are starting to weep slightly.
She is very resistant to my attempts to clean her claws, mostly it's just annoying for her but sometimes is definately painful. The dirt is caked on and quite hard on some of them.
She has never been trained to toilet indoors in kitty litter and i'm not sure it would be viable to try and teach such an old cat.
Does anyone have any suggestions for my problem?

Here's one: if you don't want to try and litter-train her now... why not put a litterbox outside that she can use if she prefers. There won't be any house accidents, but she won't have to dig in the dirt with her poor claws. If you put the right kind of litter in it and keep it clean, I'd be surprised if she didn't take to it on her own.

A cat that age needs check-ups every six months, if not more often, and senior blood panels done. When was her last check-up? I don't know what you mean by her claws are weeping, but it needs to be checked by her vet.

If it were me, I would try to bring her indoors. I would start by confining her to one room, and use a litter box filled with sterile potting soil initially, slowly mixing it with normal cat litter to get her used to it. If you don't think she would take well to being indoors at first, start slow. Bring her in for an hour at a time, and then increase the amount of time she is inside.

I would definitely have a vet take a look at her paws because you don't want her to be in pain.

Old cats really dont need to be living outdoors until they die. Maybe supervize her a little more and start keeping her indoors more. I personally would keep her in a bathroom or small room with a litterbox and see if she doesn't learn quickley. I took two kittens from my uncles farm recently, they came from about 20 generations of feral inbred barn cat and the second the litterbox was put down, they knew exactly what to do. Don't doubt her, I would move her indoors now before it's too late and get her paws healed. Especially if it affects her activeness and movement, she may not be able to escape from predators outside.

thanks for the responses, particularly from Zissou's Mum. i'll try an outdoor litter and see how it goes.
as for the weeping, it's just a little wetness at the top of her claws when i extend them out. The build up is quite smelly and i'd say easily infectious. occaisionally there are small amounts of pus. I thought it would be a good idea for me to inquire about this before it started causing her much pain.
i will take your advice and get her checked by a vet.

a point of interest may be that her father was a wild australian feral who got a local house cat pregnant. this "survival of the fittest" gene pool has resulted in an extraordinarily healthy cat who has never had any real ailments. whenever i take her to a vet they are consistently astonished at her age and comparative health. one guessed her age to be 4 or 5 when she was 16! she looked and acted like a 6 month kitten till she was about 8.

also, for the other responses, she is an indoor cat, and rules the couch. she pretty much only goes outside to toilet and then comes straight back inside again.

Do you trim her nails? Often times older cats get like toe jam on their claws, that may be what you're seeing. It might be worth while to take her to the vet and have them restrain her and trim her nails and clean up her feet a bit.