Bonded screens such as vehicle windscreens (1) bonded to a supporting frame (5) by homogeneous bonding material (6) are released by firstly arranging energy delivery means (9) adjacent the screen and subsequently transmitting energy from the delivery means through the screen thereby to effect release of the screen (1) from the frame (5) by either causing degradation of some of the homogeneous bonding material and/or cleavage or degradation of the screen material. The energy delivered may, for example, be ultrasonic or laser radiation, and is preferably arranged to be concentrated at a predetermined localized region to enhance the release mechanism.