Should I retire my harness after spilling Tincture of Benzoin on it?
Unfortunately this is a pretty easy answer from my perspective. I know some climbing companies have done limited testing on the effects of certain material and substance interaction; results can be found on their website. I can say without any scientific testing or experience with Tincture of Benzoin and how affects nylon that I would replace my harness with no questions asked. With a piece of gear that is relatively inexpensive, why not just replace it? Maybe not the answer you were looking for, but it's what I fully recommend.
—Dale Remsberg is an IFMGA/AMGA licensed mountain guide and the AMGA Technical Director.