LCD white image treatment

organ
organ Posts: 4,969
edited January 2011 in Electronics
I watch a lot of 4:3 programs on my 46" LCD and for the past 4 months or so I've had 2 black lines going down the left and right of the screen where the black bars would appear on 4:3 programs. I believe it's called "image retention" or "image persistance".

I thought it was permanent until I googled it. So far I'm no longer watching in 4:3 and stretch the image to 16:9 to keep all the pixels working all the time. I'm also doing the pure white image trick.

So far the image retention on the right side of the screen seem to be gone. The one on the left (which is more prominant since the beginning) looks like it's beginning to fade but still very noticable in some scenes.
How long does it usually take to reverse "image persistance" on LCD's?

Thanks