Assman has a
Content Filter Pipeline
that allows you to minify your scripts and stylesheets. It can minify the resources whether they are consolidated or not. To control whether a resource is minified, there is a minify property on the <scripts> and <stylesheet>
elements in the Assman.config file. You can also control whether a specific consolidated group will be minified by setting the minify attribute on the individual <group> element. The minify attribute is a boolean. Note that if you set it to true, it
will still only modify when running the site in Release mode. A site runs in Release mode when the debug flag is set to false on the <system.web>/<compilation> element.
If you want to install it manually, you will need to reference the Assman.YuiCompressor assembly from your Web Application, and then add the following lines to the plugins section of your Assman.config file:
<add type="Assman.YuiCompressor.YuiCssCompressorPlugin, Assman.YuiCompressor, Version=22.214.171.124, Culture=neutral" />