> 1) new questions containing deprecated code;

This is merely a subset of the vast category of questions asking for help fixing a problem in generally-lousy code. Problems can be as minor as sloppy naming and [incorrect brace positioning][1], and as major as injection vulnerabilities and dangerous or deprecated APIs. 

The long-accepted practice here has been to... [Answer the question](http://meta.stackexchange.com/questions/8891/is-dont-do-it-a-valid-answer). **The best way to communicate the *right* way to do something is to demonstrate it solving a problem.** Preaching at them while they're struggling isn't going to win you any converts.

> 2) new answers that continue with the deprecated code used in the question, even if the answer is otherwise correct; and

> 3) new answers that introduce deprecated code not found in the question?

**Post or up-vote a better answer**, down-vote and leave comments noting the problems on the poor answers. For older answers, [simply editing to update the code][2] can be a quick and effective solution (be sure to explain WHY in the revision comment though!)

Again, demonstrate the *right* way to solve the problem, and explain *why* it's the right way. Bonus points for making the code you're fixing simpler, shorter, and easier to understand while you're at it. Littering up a question with comments stubbornly asserting that something is WRONG without offering a concrete alternative is just annoying.


  [1]: http://meta.stackexchange.com/questions/133224/is-it-rude-to-change-someones-brackets-style
  [2]: http://meta.stackexchange.com/questions/115320/what-to-do-about-deprecated-questions-answers