( after seeing an onslaught of tweets and Facebookings on the subject, I decided to give it a look-see. These were the immediate drippings from my head-sponge)
First off, Those nails were impractical for the handling of large hammers. Second, when doing construction work, boots alone are not enough for proper safety - although the tiny tank and undies certainly offer free range of movement and good ventilation. I assume the lipstick was flame retardant and SPF 30 or above?
As for proper wrecking ball etiquette/best riding practices, nudity is not common any longer. Nude wrecking ball riding was abandoned in 1896 after a Mrs. Betty Smythson of Cincinnati suffered what was referred to at the time as "the pink twerk" (no doubt the inspiration for Miley's other musical exploration) which was the colloquial term for clitoral injury.
Mrs.Betty Smythson, "ball rider," in her
Cincinnati home, 1895
After the unfortunate ride of Mrs. Smythson, wrecking ball saddles or "Ball huggers" were instituted into common use and considered standard (although true standardization was not instituted until 1900, when the production of wrecking balls intended for riding was taken over by the Ford Motor Co.) Clitoral guards, or "vag-vests," became somewhat of a fashion statement and status symbol for upper class women who could afford the luxurious accouterments of the Wrecking Ball set.
Although Cyrus was somewhat lambasted for her "sparkly onesie" from the VMAs, it is important to understand that it was not, in fact, a "onesie" but a historically accurate "vag-vest" of excellent quality.
A 19th Century doctor attends to a woman suffering
the "Pink twerk"
Lastly, the handling and licking of the hammer, though clearly an homage to cold war propaganda communist murals, seemed a bit blatant, but not to be hasty on judgement, it is probable Miss Cyrus meant the gesture as a public service hint for Tetanus awareness, reminding us all to stay on top of our booster shots.