Occasionally I forget and buy a detector that is pretty reflective in my front window and is a pretty big distraction.
I usually throw some black electrical tape over the highlights and have done with it
It works fine but doesn't look very darn good sadly after I do.
found this nice trick to do a FAR better job recently
you need a felt marker pen, wax paper,some scissors and some adhesive backed flexible black foam sheet you can buy at Michel crafts for 88 cents or other craft places.
and some rubber cement is a good thing to have too in case you need to reposition the foam a lot !
put the wax paper over your detector and draw in the lines you will need to cut out your foam
then cut the wax paper stencil and put it one the back paper side of the foam
draw in the lines on the paper and then cut the non-reflective foam out to fit over the top of your detector and your DONE
put it on your detector and enjoy
just make sure if there is a speaker on the top of your detector to cut a opening to still hear your alerts !
if any of you give decide this a try I would love to see it.
and don't forget to remove the paper backing from the foam or the foam won't stick to your detector !