S: The ‘spurious’thermoluminescent glow from ground samples of flint is responsible for dating errors in the region of 10 000 years for grains less than 45 μm diameter or of 4000 years for larger grains. The glow is partly tribothermoluminescence and partly regeneration thermoluminescence and the conditions in which these arise or are accelerated have been found. It is shown that if thin polished slices are used rather than powder, the amount of such glow is negligible.