Jonathan McDowell noodles@earth.li wrote:
I find a combination of rejecting mail with non English content types (Content-Type:.*charset="?(ks_c_5601-1987|gb2312|euc-kr)"?) and using bogofilter helps a lot; [...]
If you add the DCC filters http://www.rhyolite.com/anti-spam/dcc/ in between these two checks, with a suitable whitelist, you should get something similar to my current set-up, probably with a similarly high success rate.