Need some HELP! i am replacing the flue for the gas hot water tank. (the flue is straight up and through the roof) the previous homeowner said that water was leaking in between the roof boot and where the flue came through, so he applied an adhesive/caulk between the roof boot and the flue coming through. The flue has some rust spots and needs to be replaced, but its now "glued" to the roof boot. How can i dissolve the adhesive, or other wise get the existing flue out to replace with a new one???