Block Flash from loading automatically and allow content only on selected sites.
Flashcontrol is a plugin blocking extension that blocks Flash and replaces its content with a placeholder. Unblock desired content by clicking placeholders, selecting the toolbar menu, or by configuring Flashcontrol's filter settings.
Included are several tools to help you manage a list of allowed sites, such as a dashboard for your filters and a DevTools panel that logs Flash URLs.
In general, Flashcontrol helps lower memory and CPU used by Flash which would otherwise slow down websites.