I used simple lamp directed to glossy table surface. One polarizer is in front of lamp and other is in front of lens of digital camera. Both polarizes are perpendicularly oriented to each other. How does this work? There is a theory about an angle on which the incident polarized electromagnetic waves turn reflects from surface with polarization plane turned in 90 degrees.
As you can see bellow in images there is no mirror reflections left.
When both polarization planes are parallel – then we see reflections
When both polarization planes are perpendicularly – then reflections are gone.
Here is a system of positioning of polarizer films explained: