Pippin Williamson

Modifies the Empty Spam action in WordPress to process the spam deletion in batches, allowing you to delete thousands or even hundreds of thousands of spam comments at once without killing your server.
Have you found a bug or have a suggestion or improvement you’d like to submit? This plugin is available on <a href="https://github.com/pippinsplugins/batch-comment-spam-deletion" rel="nofollow ugc">Github</a> and pull requests are welcome!

Batch Comment Spam Deletion

Modifies the Empty Spam action in WordPress to process the spam deletion in batches instead of all at once.

Raven’s antispam – powerful and invisible fighter against comment spam. No set-up necessary, install and forget.
<h4>Details</h4>
Visitors with enabled JavaScript (99%+) see nothing – no annoying questions, no captcha, nothing. (Users with disabled JS see an additional text-field and a word that must be rewritten into the textfield.)
Note: this plugin is not able to check your trackbacks – to handle trackback spam, it’s necessary to use some other solution. (I recommend to disable trackbacks globally, since they rarely bring any benefit for your readers.) <a href="http://kahi.cz/wordpress/ravens-antispam-plugin/" rel="nofollow ugc">more…</a>.

Raven's Antispam

Powerful and invisible fighter against comment spam.

Batch Comment Spam Deletion vs Raven's Antispam