To remove the old tag you need Zalo water, a towel and some fishing line or plastic showel of some kind. Put the towel over the dashboard and moisten the tag attachment with Zalo water. Then use the rod or showel behind the tag attachment to get it off. Do not use metal devices or solvents as they can damage the window.

You can also contact Hurtigruta CarglassRiis bilglass or Glassdrive. They will remove the tag for free.