aemeijers wrote:
diggerodell wrote:

Is the shiny side around the light bulb that illuminates the interior
of the oven? If so, replacing it with plain cardboard will be ok, but
the light level will be much less. If it is anywhere else, the shiny
side may be electrically conductive and part of the microwave system
and should not be replaced with plain cardboard. Why not use duct
tape to hold the original in place?

Uh, don't use the fabric stuff. Go get a roll of real duct tape, the
sticky aluminum kind. It is actually rated for temps as high as the
microwave box will actually get.

Aluminum foil tape withstands attic heat better than ordinary cloth-
plastic duct tape does, but alumium foil tape is not guaranteed for
high temperatures since its adhesive is often rated for only 160
Fahrenheit, sometimes for 250-300.