I could be wrong, but id swear my QID did not smell like vinegar when I got it, but after it sat in my mobile rig I think the heat made it smell so much worse.
It's pretty simple. I deep clean the trim and let it dry. I apply to a microfiber and massage it in to make sure it's in the texture. Wait a minute and go back over with a dry towel.
I would call the mobile touch up tech. Also Ask if you could get a quote from your body repair shop. They will easily be able to tell if it was a poor repaint. Do you have a shop you trust?
I would advise against using nanoskin for tar removal. The tar will not be cleaned off the nanoskin and will stay there. I believe the packaging even says to remove all tar before using.
Look on amazon for "16 inch undercarriage cleaner 4000 psi". It is an upside down water broom with wheels. Works great! I used a 90 degree before getting this tool. it is much easier now.