Hi
As timbob has said, you will probably not get rid of them altogether.
As I said before Use the bar keepers friend. With this product I have salvaged a acid pitted stainless steel sink, an enamel bath which had bleach stained residue on it and a stainless steel cooker which the other cleaning company had marked with unknown cleaning products.
This product is now part of my arsenal.
The sink in question may need a few treatments, which you can leave on for 1 minute.
As always PLEASE qualify with the customer 1st and for pitys sake take photos if possible. As they may turn around and try to blame you for it!!!
Regards
Martin
