The goal is to finish a handmade project covered with stamps. Without getting into the yak shaving of stamp adhesives, is there a material that can be used to coat the project over top of the stamp paper that will preserve the paper?

Ideas have included shellac, fiberglass (clear, without the mat), epoxy and water-based Polyurethane. Ideally, I'd like to have something that could sit on the shelf (with occasional interaction) for years without seriously falling apart. There should be no exposure to water (e.g. condensation from a glass or otherwise) nor heat (e.g. hot mug), but there might be sunlight hitting the location daily.

The goal is to finish a handmade box (slightly curved top and bottom) with hinged lid covered with stamps. Without getting into the yak shaving of stamp adhesives, is there a material that can be used to coat the project over top of the stamp paper that will preserve the paper?

Ideas have included shellac, fiberglass (clear, without the mat), epoxy and water-based Polyurethane. Ideally, I'd like to have something that could sit on the shelf (with occasional interaction) for years without seriously falling apart. There should be no exposure to water (e.g. condensation from a glass or otherwise) nor heat (e.g. hot mug), but there might be sunlight hitting the location daily.