TTN, you do me a disservice
I said we were ISSUED with 6 and only permitted to send two a week to laundry, hence the attraction of plastic. Dhobi was a non-starter as we had no laundry facilities to starch collars and indeed any such item was likely to walk. Clearly any such misappropriation of clothing was done by those cadets that failed to graduated.
Worse than collars were drawers, cellular, string, boxer like underpants with drawer cord. And better the blue and white stripped wincyette pyjamas.