From one of the Greatest blogs: Valet
I have a pair of Nantucket-red-style khakis that I've been holding off on washing so I can get more of a on them (knees, whiskering, etc). Is there a better way to do this, or am I basically pissing up a rope?
Where there's a will, there's a way. If you've been wearing them for a few weeks, you've likely got a natural crease and wear pattern developed, so you can emphasize the abrasions with some fine-grit sandpaper (look for a 240-grit). Start by lightly rubbing against the creased and worn areas, along with any other area you want to distress, like the pockets, hems and along the seams. Also, make sure your wallet's full, stick it in the back pocket and run the sandpaper over the pocket. Then take a damp rag and start rubbing where you sanded, it should help pull out some of the color and then drop them in the washing machine.