<p>Here's a simple way to use voting to clean up some crap:</p>

<ol>
<li>In the search box, enter:  votes:0 answers:0</li>
<li>Click the "Newest" tab and scroll down until you're looking at questions that are at least a day old</li>
<li>Click on one that looks bad (based on the excerpt), read it.</li>
<li>If it really is bad, vote it down.</li>
</ol>

<p>After 30 days, questions with no answers and negative scores are automatically deleted.</p>

<p>The "official" meta post with the auto-deletion rules was recently updated: <a href="http://meta.stackexchange.com/a/92006/130540">http://meta.stackexchange.com/a/92006/130540</a></p>

<p>And after reading the recently-added section of that meta.SO post, really bad questions could be cleaned up even faster:</p>

<ol>
<li>In the search box, enter:  closed:yes votes:0 answers:0</li>
<li>Click the "Newest" tab </li>
<li>Click on one that looks bad (based on the excerpt), read it.</li>
<li>If it really is bad, vote it down.</li>
</ol>

<p>After 9 days, closed questions with no upvoted answers are automatically deleted.</p>

<h2>Update:</h2>

<p>I've been searching for </p>

<p>closed:yes answers:0 score:0 migrated:no</p>

<p>for a while and downvoting the questions I think are crappy (most of the results).  Note that score:0 matches only score=0.</p>

<p>The auto-delete runs early Sat morning, so last night I checked:</p>

<p>closed:yes answers:0 score:-1 migrated:no</p>

<p>And got 1493 results.  (Note that score:-1 matches score>=-1, but there aren't too many closed q's with no answer and upvotes.)  This morning, there are only 1284 results, so 200 crappy questions have gone away!</p>

<p>As far as I can see, duplicates with no answers and -1 or less get deleted the same as other close reasons.  (Unless they were merged.)</p>