My C900 has cloth seats too.
I second what Dave T, go to a horse saddle shop and get a good leather conditioner made for outdoor leather (saddle leather). Once you get that leather rejuvenated you can use Griot's Garage's Leather Care to keep it buttery soft. Another product you can try instead of the saddle shop conditioner is Griot's Garage Leather Rejuvenator. I haven't used it myself but know some that swear by it. Griot's Garage stuff is usually very good so I would give that a try.
'00 9-5 Aero SC - '96 900 SE Turbo - '87 900 i 8v
"Never argue with an idiot,
he will pull you down to his level and beat you there with experience!"