Mafia II Definitive Edition Message Board  

First I have no idea how to do spoiler tags so what I'm about to share is full of spoilers FYI. In the part of chapter 3 when you rob the OPA building first of course you want to take all three guards. Once you do that (and this next part I do not assume everyone who might read this knows), you need to go down to the basement and turn off the alarm for the safe that the stamps are in. There are several storage rooms in the basement and when you go down there go to your left and I think it is the third room.