This trick is multifunctional, I will describe it using the example of cloning clothes.
so,
1 We go into the game (this will be game 1);
2 Create a local network (Esc, press “N” -> Local network);
3 Minimize the game, launch the board again in another window (this will be game 2);
4 Select the same character and join the 1st game;
5 From the character of the 2nd game, you can transfer clothes to the 1st;
6 When you have finished all your manipulations, exit the 2nd game and you can continue the game in the 1st;
7 Profit =)
Also, in this way, you can spend gold keys and moonstones without loss. Good luck