Increasing lamp efficiency

As a rule most school and many other theatres do not clean their lights often enough. It is one of our biggest wastes of power.I had a request yesterday from a client asking how to clean lights, so I thought I might pass it on. On Fresnels you can open the lamp tray to get at the back of the lens and spray with Windex or similar, Patt 23 lenses can be removed with a ring and cleaned, but some older profiles are a real pain to clean as you have to dissemble the lens unit to get in there, however the increase in light output and colour is significant and worth the trouble. The reflector can also be cleaned with Windex but you will not do much to help if it is corroded. It's best not to put them in a dishwasher as it can "cloud" the glass. Lights can be painted with ordinary spray enamel as they do not get hot enough to need expensive high temperature paints. If I have missed out anything feel free to add any further thoughts.