Dark areas

I bet its just worn out, wear spots will look like dark areas on lighter carpets for sure. Usually is a trail down the hall leading to the bathroom or bedroom, in front of the kitchen, infront of the couch and a circle where a computer chair would sit.

All you can do is grab a grandi groomer and try to bring the pile up as much as possible too look good as you leave.

On most light colored carpet ive notice dark areas that occur in areas where the  there might be a kid sitting playing in the same spot, or light traffic areas.  It isnt grease or oil, and I cant for the life of me seem to get the color as light as the rest of the carpet.  Ive tried a few different traffic lane cleaners with no luck.  its wierd.  It is even on my own carpet.  My wife thinks it is the dyes from the Black socks I wear.  Anyone else know what this could be?