There are multiple ways to remove a feeds.
- Go on the feed. Tap the three dots on the top bar and select "Remove" at the bottom of the popup.
- Open the left panel. Open the Settings category. Tap Edit Content. Select the feeds you want to remove. Tap remove at the bottom of the panel. To activate the Edit Content mode you can also tap and hold on a feed in the explore panel.
- Quick demonstration on how to do that: http://g.recordit.co/6UZaPRX1Wz.gif
- Click on the feed's name. Hover on "Following" on the right next to it's name, it'll turn to "Edit".
- Click on Edit and a menu on the left side will open. Click on the name of the collection this feeds is in and unmark it from the green color status. Click Close or anywhere else outside the menu.