How can I clear the cache of the Android Facebook app?

My phone (T-Mobile Pulse/Huawei U8220 with Android 1.5) doesn't have much on board space, so I quite often run into the low disk space warning. Looking through the list of apps, I see the facebook app has about 2.5 MB of user data. I suspect most of this is a photo album I looked at recently. But I can't seem to find any option to clear that cache ... Does anyone know how to? I'm happy to use a file manager and go into the filesystem to delete stuff if I can find it and someone can reassure me that I'm not going to stuff up the facebook app at the same time. And I don't want to uninstall and reinstall because [nothing will install any more](http://gadgets.stackexchange.com/questions/603/android-an-app-failed-to-download-install-what-do-i-do) .