[GfMyS0n]

Here it is,
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1. Get 2 Accounts Logged in.
2. Get Both accounts to the second trade screen (with the item your duping in)
3. The account without the item accept on the second screen.
4. Now the account with the item, you want to accept then quickly click decline
on the second trade screen
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Just as simple as that.

+rep is appreciated.