If you believe that grip is limited to your hands, you are missing the broader vision of The Art.
Are you not gripping, when your ankles are closed in the guard? When you are squeezing your knees together in the mount? When your arms are seat belted when controlling the back?
Sure, these are positions, but your are still holding onto something. If you expand your notion of grip to every opportunity where you hold and manipulate your opponent, you will find that your abilities will expand.
If you still do not believe, then take your hands away. If you consciously stop using them, you must automatically transfer your grip to something else. You will have no choice. But, when you are finished training with no hands, you will have a deeper appreciation for what grip is. You will also have a deeper appreciation for what your body can do.
Do not limit your grip to your hands. Allow your entire body to grip in the way that it was meant to.