I would say that if you want to cover your traces then selling them through local bitcoins is easy though and there could be some Bitcoin ATM's that might not have cameras installed to have look upon you unlike the regular bank ATM which keeps you under full supervision.Selling them in person is also best as only buyer and seller knows each other regardless of any third party so this option also suits me.
If you’re selling it to a person you don’t really have full privacy because who you are selling it to knows you. And if you decide to make use of a Bitcoin ATM, and the ATM happens to have cameras that monitors users, then it’s also possible that you don’t have any privacy at all.
So, I think the only platform here that is 100% anonymous when you are making use of it is localbitcoin.com, because with LocalBitcoin you just send to the buyer or to the seller and they don’t really know who you are, and before sending to them you just rely on the ratings and reviews that you have seen on their profile to do business with them. And your privacy will be maintained when you make use of this means.