Hi @
(you need an account to see links), welcome to clraik!
To be honest, selling NC items is pretty much one of the safest things to sell, since people gift out and trade NC items all the time to different accounts without getting the exchange thing on the same one and so on. So TNT won't freeze you unless someone reports you saying something like... 'this girl sold me this on clraik for real money and here's my proof' which won't happen since nobody here would think that's a good idea lol
Though, if you're selling NC items from your main account or an account you use actively, and you don't want people to know your main, you could move the items to a shell that has some boxes, and send the items from there. If you don't have shells with boxes, and you still are worried of people here knowing your acc, I would say to sell trustworthy people in clraik (like, people with a high feedback score for example). Hope this helps.