I have sold on CL before, with no problems. However, early Dec I posted a cartridge on several sites and had an experience 90% similar to @
thelostdutchman. I get an email from one joker saying that he's interested. Then I get a text from a 3rd party claiming to be his wife (1st red flag) saying that he will pay more than I was asking (2nd red flag) and that he is sending someone to drop off a check (3rd red flag) via FedEx and needed my address (4th red flag). No way I was giving it out. I strictly meet in well lit public places. Out of curiosity, I Googled FedEx & Craigslist check scam and bingo. They spelled out the exact play. The back will take the check and deposit it. However, 5 days later, you get an NSF notice.
Stay diligent. Trust but verify.