Mirrors, Magnets and Meteorites make an appearance in this week's Naked Scientists Question and Answer Show. We find out how the immune system could be convinced to fight skin cancer, how future MRI scans could be in colour, and why easy-clean computer keyboards could help keep MRSA out of hospitals. We answer your questions about inhaling helium, wind turbines, bacteria and the molecular basis of mirrors. Plus, in Kitchen Science Dave sets us the Balloon Kebab Challenge!