Floor Mat

How can I remove stains cheap light of my sticky carpet floor tile color?
I bought plastic mats cheap tiles in the kitchen. He ended up gluing on the ground (not sure if it was a mat or sealer on the tile that has caused). Anyway, I took and is not used in over two months. However, the contour of the carpet continues to appear. Clean it up, and leaves, but only a few days, the contour / spot appears again. The color is darker than the rest of the plant. What is it and why Is this happening? How do I get rid of him forever? Cleaning it day after day, it's frustrating!
A product called Goo Gone. It is in the automotive section of your local drug store.











