Runescape Account farm - Query

Okay, so I have been creating a small treasure trove of accounts (NMZ ready accs and Completed F2P starter mains) and have currently trained them all by hand and from a residential IP. If I were looking to sell the accounts, would anyone know the main steps I'd have to go through to ensure that A) The account doesn't get banned because of the transaction and B) If I need to change the emails attached to the accounts or if the client would do that themselves?

Any information regarding this matter would be greatly appreciated,

Happy scaping,

GG