Will Cache Cleaner clean JRE cache too?

No, as JRE cache is no longer an actively supported extension.

Can I clean the cache from the frontend?

Yes, you can.

By defining a secret word (in the Cache Cleaner system plugin settings), you can simply add this to any frontend url of your website.

For instance, set your secret word to: mysecret

Now you can add ?cleancache=mysecret or &cleancache=mysecret to your url, like:

http://www.yourdomain.com?cleancache=mysecret
http://www.yourdomain.com/some-page?cleancache=mysecret
http://www.yourdomain.com/index.php?option=com_content&;;...&cleancache=mysecret

So use a ? for SEF urls and an & for urls that already have variables.

Will Cache Cleaner clean the browser’s cache too?

No, it will not!

Cache Cleaner does not clean the browser’s cache - because it is impossible to do!

So you will still have to clean your browsers cache manually if you need it cleaned.