If I understand correctly, the black housings are made from a softer plastic which would be broken in in a shorter period of time. My experience with the Reds I mentioned where the completely clear housings which I believe are a harder polycarbonate plastic. The milky tops likely would be somewhere in the middle in terms of hardness, but I could be wrong. Regardless, if you are committed to using nature whites for a period of time without lubing them, they will most certainly do you well, but most people will opt to buy an already smooth switch and forgo the process completely. I'm sure any switch other than the linear Cream switches could benefit from an unlubed breakin period, so I would use any switch unlubed for a period of time anyways. I've heard of some people using cherry stems on Tealio housings for a month and then switching back the stems for a second breakin month, but YMMV on this controversial act.