I sent my 5176 for a polish to Patek and they ruined the case and returned it to me. After a lot of emails/calls they eventually agreed to replace the case. I learnt my lesson; don't listen to the people that say PP sends it back to you in a brand new condition. No such thing exists, at the end of the day they will have to remove the metal to get rid of scratches. Your watch will be at the mercy of the skill of that particular technician.