We cannot guarantee that we will remove all carpet spots or stains. There are substances that can permanently discolor the carpet fibers. The age of the carpet and the type of carpet fibers also plays a factor in this. The technician will try to determine if this is the case prior to cleaning but they are not always able to determine this before trying to remove the spots. We will do our best to examine the area to make sure that the stain is cleanable and will do our best to remove all stains.