Can I cut external insulation?

Happy Saturday folks, I'm starting my day with a clogged sewer 🥳. Anyway, to open the sewer lid I can see there is external insulation covering one side of the lid so I can't actually open it. Is it possible to just use a multi tool to cut a few mm off or in so that I can lift the lid.

Happy Saturday folks, I'm starting my day with a clogged sewer 🥳. Anyway, to open the sewer lid I can see there is external insulation covering one side of the lid so I can't actually open it. Is it possible to just use a multi tool to cut a few mm off or in so that I can lift the lid.