To the right of your watched videos, click the “Clear All Watch History” command. To do this on the YouTube website, click the menu button at the top left corner of the page, and then click the “History” option. For Google Chrome, you should try Flash Video Downloader. To download any flash video from a website, it is much easy to install an Extension for a web browser.
While all Flash videos are played using Adobe Flash plugin, it does not provide any direct option to download the video from the site.How to uninstall youtube video downloader from your pc, If you want to uninstall ytd from your system.