Yes, as fireside suggests, save the rotation matrix. One thing I would add is that you might need to clone the rotation matrix to save it (depending on what jPCT does behind the scenes, I don't know if this is necessary):
Matrix savedMatrix = object.getRotationMatrix().cloneMatrix();
And then to reset, do the same:
object.setRotationMatrix( savedMatrix.cloneMatrix() );
Egon, is this necessary, or does jPCT automatically clone the matrix in these methods rather than using the actual instance passed to them?