I've been fostering old cats for a few years now and have found the best litter to be World's Best Cat Litter. It's soya based and very fine so not 'sharp' or uncomfortable on old paws and, best of all, clumps into a neat ball, captures all the scent and can be flushed down the loo.
Only got one cat at the moment and so just have one big covered tray in the kitchen which, whenever George uses it when I'm home, I will just scoop straight away
