There were a couple of "glue/tar" spots on the rug? Not sure what it is.  But the rug is also very uncomfortable on the feet, which is the main reason for me returning it.  The knots are too big and hard.  It feels like I'm standing on rocks.  I have a pebbled floor in my shower and I love it, but this rug it at a whole different level.  It is also a lot more tan/beige in person than in the picture.  For some people, they may love it, but for me, it was uncomfortable on bare feet.