from what i know hide glue will get tacky again with heat, but im not sure if it will be enough to remove or not. in any case i dont reccomend soaking the bow in water, it will probably ruin it. maybe try heating it with a hair dryer and see if youre able to lift the sinew, and if so use a putty knife to get under it and take it off that way, being careful not the nick the back. hide glue is water soluble but im not certain the amount it would take to break it down. once you have the sinew off you could probably soak it to remove the old glue. hope this helps or someone who knows for sure how to remove it can chime in.