My favorite way to do this:
Always insist on cashier's checks.
Always insist that they be sent FedEx overnight
Always give them the address to the local FBI office.
Never give anyones actual name.
Never give a
phone number.
Always converse via Craigslist
email relay.
Change the item every time you respond. Example: "What is the condition of the engine" (scammer asking about a sailboat). Response "The
engine is in very good condition, we have only used it for one season of cutting and it's always been taken to the Cub Cadet dealer for
maintenance. If you would like, I can have the blades professionally sharpened prior to shipment".
Always insist that you did not receive the FedEx package. Act confused that
tracking shows delivery to "mail room" "Front desk" etc. Make them send another...
Call them scammers and they will just move along. If everyone who recognises scams for what they are actively frustrates them and causes them to spend resources they will soon decide to get a real job.