I think by now nearly everyone has seen those squarish plastic cling film things you throw on a window to cut glare for a passenger or child seat.
I found another use for them. Stick a couple on the sunroof to reduce interior temperatures when the car is parked all day. They also cut glair when you're driving and the sun is direct over head.
They are Cheap. 2 Axius #30003 12"x16" sheets cost less than $6 at wall mart. You can get them in tha auto section. These ones are pretty heavy plastic and should last awhile. I'm sure you can find them under other names and sizes. (They go on easier if you take the glass out.)
From outside the sunroof glass is dark enough you can't tell they are even there.
They don't take any space to store. You can open and remove the roof as normal. They can be left in place when the roof glass is stowed in front. If you don't need them, just peal them off and roll them up.
I install mine so the short ends are spaced about the width of the latch. Nearly the whole sunroof is covered by them.
I've thought about getting a replacement factory style sun shade but... I don't want the hassles of storage and installation/removal. The Cling film sheets are not totally opaque. They cut nearly all the glair and allot of heat without returning me to a "solid" roof.
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Screamin Yellow Zonkers... If it's Screamin and Yellow, I ain't eatin it.