Advice about selling a car, recieving payment via paypal.

Description

I’m selling my car (not on ebay) and have had someone offering to buy via paypal and send someone for collection. I know all about these scams where buyers say I’ll pay with a bankers draft and add shipping fees and the seller has to sort it out with the shippers. I’ve always disregarded these and said cash on collection only but this one says he’ll pay in full via paypal and arrange for someone to collect. I just want to know where I stand on the security of the payment. Do I have to wait any particular time for it to clear? Can he cancel payment once cleared or request a refund? You hear so many scams going on I just want to be sure, I’m already dubious due to the fact he’s saying he’ll send someone else to collect. Or am I just best sticking to my guns and demanding cash on collection? Please help.