Back in the 1970s, there was a real ‘natural’ beauty kick going on. Not products that were natural, but actual food items to be used as beauty products. Sunkist really pushed their lemons to be used for your hair. This 1972 ad touts that the Sunkist Fresh Lemon does marvelous things for freshly shampooed hair. Like help get rid of nasty soap film and excess oiliness. And leave your hair bright and shiny and smelling fresh.
All you need to do is just cut the lemon in half and squeeze. Or attach the handy dandy lemon juicer (which you could send for, using the coupon and 50 cents). You stick the juicer in the lemon, squeeze and pour the juice directly on your hair.