If you happen to have a stubborn stain in a place where you could indeed have a fancy pocket - why not just add one!!?
A pocket can be added easily using either hand stitching or a sewing machine. For hand stitching, I would recommend using a running stitch. I have a tutorial for running stitch here. If you are using a sewing machine, set your machine to a straight stitch.
Make sure to only sew around 3 sides of your pocket (both side and bottom) - leave the top open!
Also, an extra few stitches back and forth at the pocket opening will reinforce your seam at the point of most stress.
Nice work!! Now the stain is no longer visible and you have a funky new pocket.