Meet Pete & Harry, the Carnation Rabbits, who shilled for Carnation cottage cheese, milk, yogurt, dips, & ice cream.
Today, Carnation is a unit of Nestle, continuing the long running company's evaporated milk and Breakfast Essentials (formerly Carnation Instant Breakfast), but the wider range of products didn't survive too far past the 60's.
A quick Google search reveals that Mel Blanc (who else?) gave life to Pete & Harry, though YouTubers were convinced Paul Winchell and/or Pat Harrington, Jr. did the voices.
Following is a 4 minute montage of commercials.