I've been trying to bring the exclamation "solid!" back into the common vernacular, and it's good to see James Lileks hopping on the bandwagon with today's non-Bleat. Since he's being lazy and not archiving anything (and still getting ten gazillion hits) I'll reproduce the pictures he posted from a circa 1943 card he claims teenagers would have sent to each other.
Solid! Although, to tell the truth, I'm not really sure what "You send me solid!" means. I can think of a few possibilities, but they don't seem like things you'd put on a greeting card.
I only wish I could still find cards that began with "Look here, chick!"