What kind of solution are you using? When detailing the interior, I use 1 part Woolite to 6 parts water. Go to town on the problem areas by spraying it, scrubbing it w/ a brush and wiping it w/ some towel. A white towel would easily show you much more work is needed. In the case of the seats, vacuum to help dry it out.
I just did my mats w/c have been truly neglected (to the point you can't read the "Civic" or the "H"). Sure, it took a lot of elbow grease & patience but, I can vividly see my H logo now! Unfortunately, my driver's side requires more work and I need that mat back in the car especially during winter. At least, I can see the "Civic" now!