The plugin only cleans cache, so it does not take back old graphics or something. i think the script does this when cache is empty.

We will update our plugin with some small things like fast one click cache clean on pages.

After activating this plugin ...my site is crashed and showing an error 500 ..... can you help me out how to restore my site..... 

Error 500
Internal Server Error.

If you are the site admin, click here for details (+)

Something went wrong!
To get the error details follow these steps:
- Open ow_includes/config.php file and set DEBUG_MODE to true
- Reproduce your last action.Error details:Type:ExceptionMessage:Can't find master page `'.html_document.'` !File:/home/jsrconsu/public_html/plannerforum.org/ow_core/theme_manager.phpLine:240Trace:#0 /home/jsrconsu/public_html/plannerforum.org/ow_core/html_document.php(602): OW_ThemeManager->getMasterPageTemplate('html_document') #1 /home/jsrconsu/public_html/plannerforum.org/ow_core/response.php(200): OW_HtmlDocument->render() #2 /home/jsrconsu/public_html/plannerforum.org/ow_core/application.php(445): OW_Response->respond() #3 /home/jsrconsu/public_html/plannerforum.org/index.php(91): OW_Application->returnResponse() #4 {main}