Here's a huge Sandy's ad that ran in the Lorain Journal on June 11, 1970. (Click on it to see it in a larger size.) I like the ad because it has a certain charm to it with its liberal use of clip art.
I work in the Art Department for a company that does printing and mailing, and when I joined it back in the mid-1980s, we used to use clip art all the time in the things we designed. We had a big collection of 1950s Harry Volk Jr. Art Studio clip books that we would, well... clip out what we needed and paste it onto our keylines (that's what our artwork was called). Later, we stopped cannibalizing these books and made photostats out of whatever illustration we needed.
Nowadays, keylines, clip books and photostats are things of the past. Just like 15 cent hamburgers!