Disable loading Mootools library. It will help to save bandwidth and increase loading speed of your Joomla site. Mootools always enabled for site administrators who logged in.
In version 1.x Mootools-core.js and caption.js can be switched off.
Just install, publish and switch on plugin in settings.
You can also enable Mootools, if you need in plugin settings.
Download Disable Mootools 1.0.1 Joomla 2.5 plugin.
This plugin also supports Joomla 1.6 and 1.7.