It's very problematic question that how we remove old aggregated css and js files otherwise folder will be too large.
In drupal we have 2 functions drupal_clear_css_cache() and drupal_clear_js_cache() that are creating our aggregation files and store in css and js folder in files/css or files/js folder.
In drupal we have on special variable `drupal_stale_file_threshold` and the default value of this 30 days, it means after 30 days old aggregated file will automatically removed and we can change this 30 days value or less then 30 days like..
Code:
variable_get('drupal_stale_file_threshold', 2592000) //for 30 day.
variable_set('drupal_stale_file_threshold', 172800) //for 2 days.
Note: In drupal, we have advance aggregation module, there we have delete old aggregated files option.
Note: If have any suggestions or issue regarding 'How to remove or cleanup old aggregated css and js files?' then you can ask by comments.
