First there is the magnifying glass pin, and it is at the Dock.
The harder to get pin is the ruby pin which has to do with the play.
In this order, click the Vase, Trashcan, File Cabinet, Door, Painting, then the painting will fall and you will get the ruby pin.
There is also another cheat. Go to the back cover of the new costume catalog at the stage. Drag the “How do I get coins?” section down, and you can get the secret black Noir background.