I've used up 30% of my storage already.

With the rate I am going, this might reach the limit soon. I want to free up some of the useless or duplicate stuff (mostly attachments) that I have on my Gmail account.

Searching using has:attachment arranges according to the date, but what I really need for this is a sort according to the mail size, so that I can know which ones are eating up all the space.

Is there a way to do this that I can use?