The question is typically whether the "look" of the bathed coin is "market acceptable"... That 1832 is very borderline - maybe the luster pops more in hand than in the Heritage scan (where it looks basically "dipped out"... Also, they're usually a bit more lenient with older material - I'd say that a common late 1800's Cap & Ray or a typical Morgan with that stripped of a surface might not grade problem-free.
No one really "likes" slabs (that is, having a coin locked in a slab). If done correctly (nearly perfect on
Counterfeit Detection, noting cleaned/altered surfaces, proper evaluation of the degree of wear), they definitely serve a purpose on theory. That's why the initial "AU 50" in the thread is bothersome... undermines credibility.