The wall will not break by simply removing crown molding. Make a cut line with a sharp box knife/Stanley knife at both the edges of the crown where it meet the wall and the ceiling, this will cut any caulk that was added when it was installed and stop pulling the paper or paint off either surface.
I like to start in the middle (of a single piece) or at a joint and with a 7 in 1 painters tool gently pry the crown from the wall and ceiling (taking turns so as to not force it any one way) by alternating between top edge and bottom edge you will be able to pull the crown out from the wall/ceiling on a rough 90 degree angle from the corner, this will also help with nail removal. Take your time and work your way to the corners, depending on the install method the corners will either be mitered to each other, or one side will cut in behind the other, if the later you will have to pull the crown out from behind, be careful not to rush as you will damaged the over payed piece. It is best in these install cases to remove the over laid crown first.
Tip: when removing the nails from the crown do not hit them back out in reverse, you a nail puller or a good set of pliers and from the back of the crown pull the nails all the way through the piece of wood, this way there is no damages to the finished face of the crown.