If the stretch marks are caused by the pregnancy, it should fade away by itself eventually. But id it is caused by weight loss, some cases require laser treatment or something like that. If those are just minor stretch marks, skin lightening creams can be used (the one without hydroquinone please). You can also try natural products like lemon juice, etc. But if it's on the part of your body that is unlikely to be seen, don't bother removing it anymore.