Hi Peter, I like your avatar image, but for those who don't know you in person they might assume you are slightly cartoonish instead of the handsome poised proper Englishman you are;>) Last trip was so hectic and ended a week early that my time this next trip will be much more flexible so would not miss seeing you and Celia for anything. PS, we tried your recipe you so kinding provided but it was not anywhere as delicious as how you made it. I think the chef's touch, as in all things from photography to Margaritas, makes a difference.
Eclipse Cleaning fluid is easy to make, the primary ingredient is dimethyl carbinol which for us laymen is isopropanol, IPA. Add a bit ethylene glycol butyl ether or as it is called more commonly, Butyl Ether. It costs about $ 3/gallon so there is a profit to be made selling it in 1 oz bottles to your camera club;>). You could leave out the Butyl Ether but both ingredients together are a little more effective. They both are effective as solvents for most organics but the Butyl Ether is also a good solvent for fat soluble substances that alcohol is not. Water is the best solvent but does not dry fast enough with no residue unless highly pure. A good method would be multistep, first distilled filtered water as solvent then, before the first it allowed to dry, isopropanol which is good as a solvent for things that water isn't and has the added bonus of absorbing water that might be left behind that can cause spots. Most of the commercial glass cleaners are ammonia and isopropanol and if it has a slightly sweet smell, it also has some butyl ether added in. Any fast drying organic solvent will be safe for the sensor but commercial products usually add a lot of colorings and fragrance chemicals that are useless as solvents and might streak with residue. Stan St Petersburg Russia