Here's a test to see how old you are: Do you remember car-window frost shields?
For those who don't, they were squares of plastic -- slightly raised -- with an adhesive strip around the edge. You stuck them to the inside of your car windows and the vacuum created in the space between the plastic and the glass kept the inside of the window from fogging or frosting up in the cold. (The Ashdown's ad markets a more expensive version consisting of a sheet of glass with a rubber gasket.)
Frost shields burst onto the automotive scene in the winter of 1926-27, long before front- and rear-window defrosters were a gleam in the eye of an automotive engineer. They were soon a standard part of a basic winter tune-up, along with radiator grill covers and winter anti-freeze.
In 1937, it became law your windshield, rear window and front-row side windows had to be fitted with frost shields from Dec. 1 to March 31. When spring came, the car owner then had the unenviable task of trying to remove what was left of the shield and its adhesive residue.
As windshield defrosters became more commonplace in the 1950s and rear-window defrosters in the 1970s, the demand for frost shields diminished. You might be surprised to know, though, their use is still noted in Manitoba's Highway Traffic Act:
Frost Shields Required
57(2) The windshield, rear windows, and windows at both sides of the driver's seat, of every motor vehicle at all times between the first day of November in each year and the thirty-first day of March next following, both dates inclusive, shall be equipped with adequate frost shields of a size and type that will prevent or minimize the condensation thereon of moisture in the atmosphere and allow the driver to have a view sufficiently clear and unobstructed to permit him to operate the vehicle with safety to other persons and vehicles on the highway, unless the vehicle is otherwise so equipped or constructed as to secure a like result.
Winnipeg was a hub for the manufacture of frost shields. In the mid-1940s, there were at least four companies that manufactured them. James B. Carter Ltd. was likely the largest and sold them across the country. Through various mergers, the company became Temro Phillips, which still manufactured interior car heaters in Winnipeg until the plant closed in 2012.
In case you think frost shields have disappeared into history, they haven't. They are still used in construction equipment, helicopters and outbuildings. The only company I could find that still manufactures them is, of course, right here in Manitoba: Custom Tarps and Filters in Brandon!