How do I delete iPhone notes from Gmail?

I would love it if I could delete conversations on Gmail for iPhone and iPad because I hate dragging out an email chain just to remove one message. Also, when I archive something, that action seems to appear as deleting the email – which is confusing. Is there any way to do this?
Unfortunately not; however, you can still delete certain emails within the conversation by tapping More > “Move” then selecting “Trash”. This deletes only that single piece of correspondence without touching others in the same thread. Alternatively, you can try using the web version of Gmail instead, where we’ve found a more flexible set of actions available via a long press of an email: tap More > “Move to” then select either Trash or another label.

On the Settings screen, it says that you can stop syncing your Notes when you turn off Mail or iCloud.

Choose the type of note you want to delete by tapping More > a single note or several notes at once. To delete, tap the (i).

Open the Gmail app, sign in to your correct Gmail account, and tap on the 3-lined icon in the top left. To find out notes from any other apps you use with Google’s functioning for Notes as a search tool, scroll down until you see “Notes” under Labels.

Click the Notes button in the Navigation pane. The list of notes appears. Click the note you want to delete and press Delete on your keyboard or click Delete from the Ribbon. Your note is deleted correctly!

Now to view the Notes, log in to your Gmail account on a browser or the app and scroll down.

I’ve been using Google+ for a while but one thing that always frustrated me was being unable to remove threads once they’re old and irrelevant – mailing lists, groups, etc are still very much alive and well in there! Is there any way of making them go away? I can take down posts by offending parties, but not the whole conversation.