February 2012. Silvery-shiny spots that can be scraped off, randomly over the skim of still green fruits. What causes them? The photos were taken in Trinidad and Tobago.
There were several suggestions:
the result of mechanical damage as the fruits rubbed together in the wind when they were younger
slugs and snails were considered but rejected as the cause
latex from other fruit or damaged leaves have dripped on the fruit.
[Editor]: The last suggestion seems very likely as the marks can be scrapped off, somewhat.