How to Remove Brown Pinstripe from a Branch?

I finally got my white GC washed and found a brown pinstripe about a foot long from a recent trail. At first I thought it was sap but neither WD40 nor naphtha did much. I can feel that the clear coat and paint are a little damaged, but all I want to do is get the brown out so it’s not so visible. Any suggestions?

Nevermind, I tried some isopropyl alcohol and it came off.

And I was wondering why would someone pinstripe a branch?

Ha, yeah that could have been written better!