I made a change to an admin component, but it's not reflected immediately. Is there a way to make the admin cache refresh? I know with modules you can set cache to none, but this is a component so I don't have that option.
Yes, there is a way. It is called Cache Cleaner, extension from Regular Labs (ex-NoNumber).
With Cache Cleaner you can clean your cache fast and easily via a link in your Joomla! Administrator.
Not only that, it also gives you the possibility to purge expired cache, do a global check-in, empty the temp folder, empty user-defined folders and database tables … all with just 1 click!
Cache Cleaner can clean your cache automatically when you save an article or other item. And it can clean your cache at preset intervals too. So no more clickety-click to get to the core Joomla! Cache Manager and no more manually deleting files.
Let it be noted that the extension cleans up both /cache folders (site's and admin's), even though that is not explicitely written in description.
I have been using it for ages and can't imagine my work in Joomla admin without it.
Login to admin panel, see top menu, click "System", click sub menu "Clear Cache", I think rest you will understand.