Farming Precious' Ribbon

From the Wowhead Comments

<UPDATES>

Do NOT kill Festergut or Rotface, just Precious. Make sure to "Reset Instances" before entering the 25 instance. You don't need to reset after each 25 run, just the initial instance of 10 normal.

Guide for shadowlands farming: enter icc 10 normal, kill the first 4 bosses, then kill Precious next to Festergut and Rotface. Go out reset instances, enter icc 25 normal, use teleport to 4th floor kill Precious again. Repeat this until you get the shirt. Got it on my 4th. try, gl!