Removing Mill Scale from Plate

[GPintheMitten]

Theory of origin is that if you can put two and two together and get four then it is a rather obvious conclusion. The part about getting four was dropped.

 

[dragoneggs]

Theory of origin is that if you can put two and two together and get four then it is a rather obvious conclusion. The part about getting four was dropped.

Yeah I guess because in chemistry that doesn't apply!