There must have been a theory once that 3 letters was the optimal amount for a detergent name. And the bigger the letters the better.
I'm guessing that this was so that you could see the box from over a hundred miles away.
Or maybe the ad men just figured the American public could only remember monosyllabic words.
They must have run out of creativity after a while and started coming up with four letter one syllable words. What's wrong with PUZ, SYZ, LEP, SUK, PUD, NIT, TWA, SOP, FEP, TOX, GIK, ITP, PMA...?
Uh-oh, this might be getting too complicated for the masses.
I like the simple designs though.
Dreft is a classic. 
Some ad genius went against the current thinking and came up with a word that actually takes some tongular dexterity.What a great name and design! You get a free Chix with every Dreft you buy too!
The ads follow the same old easy to read hierarchical thinking.
Judy Garland got her beautiful complexion and singing voice by washing her vocal chords in the toilet with LUX Larynx soap.Here she is looking just like Barney Fife and singing with extreme virtuosity one of the most emotional songs ever written.
She could only pull that off with the right toilet soap. Look what it did for her hair too. That scouring pad on your head look that was so popular in the 60s. Seriously though, I think she is a genius.
Here's a great design for tooth detergent.I bet all these products sponsored their own TV shows too and we got to see rich stars doing their own washing and even brushing their own teeth. Maybe Rochester brushed Jack Benny's teeth after each long smooth Lucky Strike cigarette.
