# To turn on JS Aggregation
    drush vset preprocess_js 1 --yes

# To clear all Cache
    drush cc all

# To disable JS Aggregation
   drush vset preprocess_js 0 --yes

# To clear cache of JS and CSS only
   drush cc css+js

# To enable CSS Aggregation
   drush vset preprocess_css 1 --yes

# To disable CSS Aggregation
   drush vset preprocess_css 0 --yes
   
# source: http://danreb.com/content/how-quickly-enable-or-disable-drupal-cssjs-optimization-using-drush