I have recently been learning another language and when I explained what I do, the need for the word 'volunteer' came up fast. 'What's the word for someone who works without pay?' I asked.

'A slave.' said my teacher.

Ah, yes. You know non-profit slaves! People with smarts and ethics and education who you stuck photocopying pages for an hour. Or markering a poster. Those slaves, the ones that don't come back after your first slave meeting.