Make Mendeley, BibTeX, and apacite play nicely together by removing URL and month entries. Apacite lumps journal articles and newspaper/magazine articles in the same class, and always prints a month if it's provided. This gist has a shell script that strips this info out and a launchd handler that watches the auto-exported .bib file and runs the…

clean-library-auto.plist

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>Label</key>
    <string>auto-clean-mendeley-library</string>
    <key>ProgramArguments</key>
    <array>
        <string>/Users/dkleinschmidt/Documents/papers/clean-library-auto.sh</string>
    </array>
    <key>WatchPaths</key>
    <array>
        <string>/Users/dkleinschmidt/Documents/papers/library.bib</string>
    </array>
</dict>
</plist>

clean-library-auto.sh

#!/bin/bash

cd /Users/dkleinschmidt/Documents/papers

# remove month and url lines in bib entries
egrep -v '^(month|url)' > library-clean.bib < library.bib

# write a message to the log
/usr/bin/logger library.bib modified and cleaned

start.sh

#!/bin/bash

# this whole solution was adapted from 
# http://stackoverflow.com/questions/1515730/is-there-a-command-like-watch-or-inotifywait-on-the-mac

# you'll have to change the hard-coded locations to match whereever you put these
# files and Mendeley exports the .bib file.

# install the watcher using launchctl: 
launchctl load /Users/dkleinschmidt/Documents/papers/clean-library-auto.plist