grunt-contrib-cssmin - how to remove comments from minified css

Im using cssmin to minify css files.

my config like this:

module.exports = function(grunt) {

    grunt.config.set('cssmin', {
        site: {
            src: ['.tmp/public/concat/site.css'],
            dest: '.tmp/public/min/site.min.css'
        }
    });

    grunt.loadNpmTasks('grunt-contrib-cssmin');
};

But output minified css files has comments. Is it possible to configure cssmin to remove comment from source css files?

Thank you.

Set keepSpecialComments to zero, for removing all comments.

grunt.config.set('cssmin', {
    options: {
        keepSpecialComments: 0
    },
    site: {
        src: ['.tmp/public/concat/site.css'],
        dest: '.tmp/public/min/site.min.css'
    }
});

For future reference: grunt-contrib-cssmin uses clean-css options.