That piece you are pointing to is the anti reverse. I is supposed to be clean and dry. I’m not sure how you are going to fix that, maybe with Qtips and alcohol. I would never take it apart. I did that once. Once was enough.
When I do bearings, I soak them in acetone, dry them out well, then put no more than 1/2 of 1 drop of Shimano oil on each one.
I’m guessing what you are now feeling is your anti reverse binding because of the oil.
Where are you located?