Are his paws all clumpy and dirty or they just smell? I have had a lot of experiance with sphynx (those darling furless) and some mixed breeds who had greasy nails. Those had to be cleaned with weekly baths but I found out the shower mittens they make for human bathers work really nice on kitty nails!
A few other thoughts... If his feet are dirty from clumping cat litter then something's a bit amiss. He's probably playing in the water bowl before or after using the box. Figuring out how to stop that would certainly help.
"Soft Paws" might help too. They're to stop furniture getting all scratched up but since they're smooth they might avoid picking up so much dirt.
And if you don't have a well-used scrtaching post I deffinately advise it. Much of the dirt a cat picks up is dislodged when they're scratching at things. Plus the nails themselves shed their outer layer fairly frequently, and this usually happens when they're scratching at something.
Lastly, I had a sphynx once who ended up covered in wet cat food I was prepairing when the bowl flipped. Long story short all the other cats dashed in and cleaned her up for me! Perhaps you could use this wet meat gravy tecnique for your kittie's front paws? Worth a try and it wouldn't hurt him any. He'll probably just think it's a treat. :)