First, since reddit uses lazy loading (new reddit), scroll as far as you possibly can on the subreddit (until you hit the last post). Then, run the following script in the console (for Chrome: Ctrl
+Shift
+J
on Windows or ⌘ Cmd
+⌥ Option
+J
on Mac):
const removeButtons = document.getElementsByClassName('icon-remove');
for (let i = 0; i < removeButtons.length; i++) {
removeButtons[i].click();
}