They make a spray for your license plate.

BloomingtonMike wrote:
I've heard that those don't really work ....don't know. Do you know of any that work 100%?

The spray does not work...at all. Mythbusters did an entire segment on it...even at a 100mph+, it still didn't work.

Jetman wrote:
That's what I heard.

BloomingtonMike wrote:
I guess this is a controversial subject. Is there a certain brand you know, or tried any of this yourself?

We have Redflex speed & redlight cameras in our town. Ours do not fire strobes in daylight, so, I question if the spray would have worked anyway. Also, here is MythBusters results:

Episode 73: Speed Cameras
Air Date: March 7, 2007

A speed camera cannot see through a crystallized plate cover.
BUSTED
In the crystals inside the cover did not reflect enough light to fool the camera. Also, the legality of such a device was questioned.

A speed camera cannot see through a lenticular lens plate cover.
BUSTED
While designed to distort the plate from an angle, all or most of the letters of the plate were still identifiable in the tests. Also, the legality of such a device was questioned.

A speed camera cannot see through plastic wrap.
BUSTED
The plastic wrap proved to be ineffective.

A speed camera cannot see through hair spray.
BUSTED
The hair spray was ineffective.

A speed camera cannot see through commercial spray PhotoBlocker Spray.
BUSTED
The commercial spray was ineffective.

A speed camera cannot take a picture of a car if it is going fast enough.
BUSTED*
Neither a normal car nor a Lamborghini Murcielago LP640 were able to travel fast enough to outrun the camera.

*This myth was revisited in episode 84 with a jet-powered car and it was confirmed.
A speed camera can take a picture of a passing bird.
CONFIRMED
The speed camera managed to catch a pair of trained peregrine falcons passing it at a speed of 40 miles per hour