Well, I wouldn't know exactly how to do it but I know that bitcoin is traceable, so what I would do is transfer it to monero, then from that monero wallet to another and then back to bitcoin, in the end you create an anonymous bank account and you transfer "small" amounts of money from anonymous to real, another way is douing al theese but in stead of transfear it to your bank transfer it for games money, like robux and after that sell the accounts, I'm not 100% if it works but I've been thinkin on these for a wile