A DUO DISCUS in the United Kingdom has been destroyed after a fire started in and around the main wheel housing. The disc brake was left on while the aircraft was ground towed. I have also heard that an ASK21 in Australia generated a fire by dry grass catching fire near an overused disc brake (fire extinguished) and an Eagle sailplane was destroyed by fire after brakes catching fire. Fibreglass gliders and the over-use of disc brakes do not mix and perhaps we should consider carrying a $20 dry powder fire extinguisher (Supacheap Auto) in big two seaters during dry summer periods. Perhaps timely to advise on the correct hydraulic fluids to be used in wheel brakes - Tost master cylinders require “DOT 4”. Schleicher gliders are fitted with Cleveland brakes and Cleveland master cylinders require MIL H 5606 only.