Recently my local cobbler introduced me to the Tacco eraser. It is a cleaning eraser for suede, velour and nubuk with tiny sand particles. You can use it on shoes, clothing and handbags, and I must say the results are remarkable. This "eraser" removes the stain without destroying the nap of the suede.
Before (ewwww... I know)
It's not 100% removed, but a pretty significant improvement, without having to use any sprays or liquid cleansers that could alter the colour or texture. I even went over the straps and around the sole closest to the ground to remove dirt and any little black marks or scuffs that I got over the summer. I love taking care of my shoes.
(sandals Balenciaga- THE most uncomfortable sandals in my closet)