Receipt collection for Clay
Cardboard automates the collection of receipts for payments made through Cardboard, so you don't have to collect the receipts yourself.
Receipt fetching with browser extension
The Cardboard browser extension can upload the receipts for this service.
All you need to do is go to the page where you can download or view the receipts. The extension will let you know which of the receipts are missing from Cardboard and you can upload them in one click.
The Cardboard browser extension is only available for Chrome- and Firefox-based browsers.