Duct foil tape is commonly used in home heating and cooling systems, and often is used to create a vapor seal. Foil tape binds particularly well to sheet metal. It is not sensitive to temperature and can be used in freezing, normal or high-temperature situations. Over time, the glue on duct foil tape hardens and loses its elasticity. Though it rarely needs to be removed by nonprofessionals, you can remove duct foil tape with little trouble.
Slip the edge of the straight razor under the end of the duct foil tape you want to remove. Slide it under the tape until you lift a tab that is separated from the surface to which it was adhered.
Fold the edges of the tab toward the middle to create a triangle.
Press down on the duct foil tape that is still adhered to the surface, about an inch away from where you created the tab. Pull up on the tab slowly to remove the tape. If it will not come up with pressure, slide the razor between the duct foil tape and the surface to break the seal, then pull it up and away with the tab.
Put on a pair of gloves. Spray industrial-strength cleaner on the surface.
Wipe the surface with a sponge to remove any remaining residue. Residue may not form if the duct foil tape has not been on the surface for more than six months. You do not have to remove the residue.