I assume you’ve seen an ad from one of the recent bumper crop of money-for-gold companies?
I have a business proposal for you.
We rig up a computer to a modified high-heat oven, and put it up against a mail slot.
When the mail gets delivered, it drops onto a small sorting unit which separates things out into individual letters. The letters are scanned, then the ends are cut off. The gold (which we’ve released a marketing campaign offering to purchase at not-quite-gouging prices) is dumped from the torn envelope and into a smelting unit, which heats to exactly gold’s melting point, and mechanically separates anything else that might survive (diamonds).
The gold is set into blocks, which are then weighed, and a feeder unit dispenses the proper amount of money (as well as any of the other odds and ends that survived the smelting process) into an envelope, which has the address pre-printed with the location originally scanned from the letter-face.
Once a week you take some of the money we’re now rolling in, insert it into the pay-out hopper, check the envelope & ink supply, grab the outgoing mail, then walk off to a fancy party with your pockets full of gold blocks.