What does the saying, "grey coat on, grey coat off" mean?

Apparently, it was a saying used back in the goodol days amoungst the Army lads when having to chop & change tasks all the time. Just trying to find o

Apparently, it was a saying used back in the good'ol days amoungst the Army lads when having to chop & change tasks all the time. Just trying to find out if there's anymore to the story.

or:Apparently, it was a saying used back in the good'ol days amoungst the Army lads when having to chop & change tasks all the time. Just trying to find out if there's anymore to the story.

Tags:good,