How do you clean Stan Smith Adidas shoes as white as it was before?

My Stan Smith Adidas shoes have gotten dirty in 2 weeks of me buying them but usually when i clean them, some of the dirt doesnt come off or it doesnt leave the shoes white. Ive tried using them in the washing machine but thats only made the material more brittal. Any suggestions?|||buy some adidas clear balsam, its a miracle|||bleach or specialized shoe cleaner for leather that can be brought @ footlocker etc.