Here are the instructions:
=> Get a Bottle of Blood - Goto sewers and find the hidden room - Here is a script to buy it: https://pastebin.com/raw/iQdZTxa8
=> Now get ur alt to trade you (the alt without blood)
=> Equip the Bottle then Execute the script from this post
=> Put in the blood first into the trade
=> Then put in the items you want dupe