The SpamAssassin plugin provides anti-spam capabilities for Claws
Mail. SpamAssassin is a complete spam checker, featuring local
tests, remote tests, Bayesian filtering, and more. It is written
in perl. This complete set of checks makes it really good at catching
spam, at the expense of filtering rather slowly. Claws Mail also
provides a Bogofilter anti-spam plugin, which does only Bayesian
filtering, making it faster than SpamAssassin. The SpamAssassin
plugin features are:

	* Filtering spam when mail is received, and moving it to
	  a specific folder or destroying it completely
	* Learning what is spam and what is ham, in order to better
	  filter your mailbox
	* The ability to use a remote SpamAssassin server for
	  filtering and learning

SpamAssassin can begin filtering your emails right away, as it
isn't only a Bayesian filter; but you should correct it with the
learning feature if you get false positives or false negatives.