I was so disappointed when the USPS rejected my postal-stamp-sized envelope. It would be cool to have a service (maybe one already exists?) that specializes in

I was so disappointed when the USPS rejected my postal-stamp-sized envelope. It would be cool to have a service (maybe one already exists?) that specializes in the processing/fulfillment of machine-unfriendly mail pieces. Reminds me of this guide: https://thepostmansknock.com/how-to-make-deliverable-mail-art/ https://thepostmansknock.com/how-to-make-deliverable-mail-ar...