…Someone’s been drawing on the playground after school with coke…
Your guess is as good as mine.
Twenty-five years ago today
A real-time rummage through my old diaries
…Someone’s been drawing on the playground after school with coke…
Your guess is as good as mine.
Twenty-five years ago today 
Could coke refer to coal, rather than the fizzy pop?
“Coke” was what my grandparents put on the coal fire. And cinders were known as Clinkers.
Despite sounding like the sort of antics carried out by a kid in the 1880s rather than the 1980s, that does semm more likely than a bit of soft drink-based hooliganism.