Yes, the Kennedy half dollars are ugly! 1964-present
The Walking Liberty half dollars are much more beautiful 1916-1947

And what did they do to those half dollars? Bathe them in urine? Maybe some cleaner?

It is interesting that that year, 1964, is the only 90% silver Kennedy half dollars.
The next year, half dollar was dropped to 50%. And 1971 dropped to nothin