Holding the mouthpiece under a hot tap is usually enough to break the seal of the adhesive.The mouthpice can then be moved out to flatten the pitch. If its a D whistle tune to the centre notes - the G or the A as this will minimise any inbuilt errors in the finger holes.I dont normally respond at all to anonymous posts but our Guest is correct in that there is often an error in tuning on the lower priced whistles, AND sometimes on the pricier ones too.I wont buy a whistle without trying it out for tuning AND the ability to get into the third register.