mrbluze writes: The standard kilogram weights which are used by countries around the world for calibration have variably increased in mass by tens of micrograms. This poses a threat to the precision and comparability of measurements in science, engineering and trade. The problem is due to surface contamination, but a safe method of cleaning the weights has only recently been devised by the use of ozone and ultraviolet light.
"Card readers? We don't need no stinking card readers."
-- Peter da Silva (at the National Academy of Sciencies, 1965, in a
particularly vivid fantasy)