[Mike Cottam]

I was asked to clean this wool rug. I opted for dry cleaning but cant seem to lighten the dark area along one long edge.

It may be darkened due to being placed in front of a fireplace at some stage.

Any ideas?   

[Mike Cottam]

[sean oregan]

Spillage, soot or diy clean I would say

[Dave_Lee]

Has a look of shading, pile reversal etc. Area of pile going in the opposite direction to the  remainder. This could be confirmed or ruled out by looking at the rug from the opposite direction to see if that area became lighter and the larger area became darker.
Dave.

[Paul Moss]

It's pile reversal or may be uv colour change. I would guess it has had a large heavy object stood on that era for a long period if time.

[Shaun_Ashmore]

All of the above Paul's idea would be my guess as well but it also could be water damage causing pile reversal, you need to ask your customer more questions.

[Paul Moss]

The line is too straight for water damage, it's either sun or something heavy has been sitting on it.

[Jor dan]

stumped!

[Hilton]

Looks like shading/pile reversal, you would have to get down and have a look.

If it is it is irreversible.

[Mike Cottam]

Thanks everyone, it's actually pile distortion. Had I simply walked around to the other side of the rug, I would have worked it out myself as the dark patch does disappear!

Schoolboy error...