I bought some Buddy Demister spray from Lakeland Limited last year, not really expecting it to work (but I'll try anything if it looks like it'll make my life easier!). It prevents mist and condensation from forming on mirrors, windows, shower screens and other glass surfaces. You first clean the surface, then spray some demister spray onto a clean cloth, apply to the surface, leave to dry, then buff it with a dry cloth. It is really easy to use and leaves surfaces streak free. The good thing is your mirrors etc do not look dirty as soon as there is no condensation dripping down the mirror causing streaks. I have found that I do not need to clean the mirror anywhere near as often and the effect from the demister lasts a couple of weeks. Also after having a shower you don't need to wipe the mirror, which normally leaves the mirror looking a mess. I have only seen this product in Lakeland Limited who do mail order and on-line shopping, as well as selling it in their shops.