There are some useful YouTube videos on this topic. A couple highlites: Heat helps, but as previously mentioned, not too much or gel coat damage can occur. Also, use PLASTIC razor blades, available on Amazon. Anything metal can damage the gel coat. Lastly, usually the gluey residue is harder to get off than the vinyl itself. If Goo-Gone or Goof-Off doesn’t work
, 3M makes a rubber wheel
that goes in a drill called an “eraser wheel” that works like magic. But it’s pretty pricey.