Use Safe Boot to Clear Font Caches.
If you suspect that fonts are causing problems in your applications, an easy troubleshooting step is deleting your Mac’s font caches.
We've covered font cache problems before in our Garbled Fonts Troubleshooting Guide — which delves into font problems more deeply. However we did overlook a quick and easy method to delete font cache files.
In Mac OS X 10.4 Tiger, you can delete font caches by restarting your Mac in Safe Disk mode. To do that, start up with the Shift key pressed until you see the term Safe Boot in red letters. Then release the Shift key and log in normally.
Booting in Safe Disk mode turns off things that normally load (including font managers like Extensis Suitcase or FontAgent Pro), does a disk check, does some housekeeping, and deletes the font caches located in your Library/Caches/com.apple.ATS folder.
You’ll want to restart right away after a Safe Boot.
Source: This tip comes from this month's issue of Design Tools Monthly. Members of a CreativeTechs support plan receive a subscription to Design Tools Monthly in their monthly care package.