DrJean said:There are "black out " curtains and drapes you can buy... I have them in my current (soon to be sold?) house.
I bought some blackout curtains for my living room, but even after weeks of letting them air out in the sun, they still give off that toxic burning-plastic smell that means they're off-gassing. I don't relish the thought of being stuck inside a hot car with something like that. A regular all-cotton bedsheet strung up on a taut wire between the front-seat handholds might work, but I'd need to figure out what kind of wire to put up (fishing line?) A tensioned shower curtain rod would work too, but I'll be sleeping right up against the hanging curtain and I'm wondering whether one accidental tug on the fabric during sleep might send the rod crashing down on me....