Scams when selling on Craigslist or ebay

I got mailed a check for 2200$ for a engine block I was selling for a grand contact number was from California check from a bank in Carolina ... legit looking watermark business check and item was to be shipped to Texas lol the scam isn’t getting the part but getting u to refund the difference in over payment .
Have had that request already. Also 'I will send money and someone will pick it up'. That one I believe is akin to 'check is in the mail'. They want to grab the item and you never see the money.
I tell them cash on pickup. I don't care who you send.