Mnifi JS

Similar plugins also allow you to minify js. I would like to stick to your plugin however. Is there a possibility to minify non-header js?
Google PageSpeed Insights shows me with your plugin:

Minifying http://paleosmak.pl/…/twentyfourteen/js/functions.js?ver=20131209 could save 560B (40% reduction) after compression.

https://wordpress.org/plugins/asynchronous-javascript/