The building itself changed little over the years, even as the parliaments meeting inside it did. To camouflage it during World War II, the building's Portland stone was painted with supposedly removable "paint" made of bitumen and cow manure. However, after the war, removing the paint proved an enormous difficulty, with the paint having scarred the stonework. It took seven years to remove the "paint", and the exterior façade has never regained its original white colour. While most traces of it were removed from the façades (though having done damage that can be seen up close), some of the remains of the paint survive in the inner courtyards and unseen parts of the building.