The donor roof I purchased had good gutter trim, so I needed to remove it before the roof swap on my Sprint project this week.
As it was in good condition I thought I would try to remove it without damaging it. I have done this a few times before but couldn't really remember how.
I remember reading that Alun suggesting using an old pair of pincers.
I started at the back using a wide blade screwdriver under the bottom lip to get it started as the pincers wouldn't fit against the c post, then using a thin piece of softwood & the pincers gradually prised the trim off from under the gutter, I did this in small steps along the whole length & it came off undamaged & only took about 15 minutes each side once I got the hang of it.
If your car is not going for paint afterwards it would be worth sticking some masking tape on the underside of the gutter to protect the paint.