With the release of Leopard, Apple have hidden the cache and temporary files away from prying eyes and mouse clicks. Instead of being located in the /Library/Caches directory, Apple have moved the font caches to a new home in the /private/var/folders directory structure.
To find the path of the current users cache directory, use the following command in the Terminal:
This will return a string that will look something like this:
Now, you can navigate to this directory and manually delete the com.apple.ATS folder within, or you can use the new atsutil al follows:
atsutil databases -removeUser (to remove the font caches for the current user)
sudo atsutil databases -remove (to remove all user and system font caches)
As with previous version of Mac OS X, you will have to immediately restart after clearing the font caches. Always quit all open applications (aside from the Terminal), saving any documents, before cleaning any caches. This will prevent future headaches.