It's easy to search for attachments in Gmail. This tip will help you search by the size of the attachment
To search for attachments in Gmail, use the search parameter has:attachment. This will show up all your emails with an attachment.
If you wish to find attachments over a certain size, you can do this using size:
So, to search for large attachments you could use the search size:10M
This will show all emails with attachments larger than 10MB Try it now
Combine this search with the older_than parameter to find mail older than a certain period.
For example older_than:1y will find mail more than 1 year old; older_than:30d finds mail over 30 days old. Try it now
Let us know what you think of this tip in the comments below.