I cleaned the windscreen after a run the other day, and because I’d run out of the proper stuff I used ASDA glass cleaner “with vinegar”, green in colour and <£1 per spray bottle. It seems to have done an excellent job. It seems that I might have been paying over the odds for (e.g.) Halfords glass cleaner to do the same job. Has anyone else used a domestic rather than a dedicated automotive product?
Vinegar in water has long been used by those of a certain age to clean windows.
And newspaper is good for removing smears. Actually, it’s more productive to use newspapers this way than to read the crap currently inside them 
Hear, Hear.
I recommend Autoglym Fast Glass. If it is real dirty, try
Car Glass Polish, you put it on like SRP.
Domestic cleaners can make the plastic parts turn grey, reuin the wipers, and they strip wax or sealents off paintwork. Car glass cleaners do not do this, and they also make water sheet off the glass rather than having water marks.
I use “Windolene” spray that has vinegar added, (probably very similar to the Asda product. It was on a 3 pack special at Costco a while ago, so I bought some. It works a treat and is smear free too.
well, its the other way around here… I’ve used automotive stuff in the house, as I know I can get a smear free perfect finish with autoglym fast glass (and the polish as well) but no way can I with any of the household rubbish the wife buys…
i use the dodo juice glass cleaner cant remember its name in the summer and rainex in the winter ;D
Charlie
I have used vinegar to wash and newspaper to dry and polish the glass many times mostly on the company car oil buner works great I have found when you use the air con you get a heavy soiling on the inside of the screen the vinegar and newspaper well good
Alan
I am not sure how true this is but, have been told you never clean glass in sunlight. When I tried the bungalow windows I couldn’t get rid of the streaks when polishing them after using cleaners.Never had any more problems since cleaning the car and bungalow windows in the shade or non sunshine days. Try it yourself and see if you find the same.
I use Autoglym Fast Glass as well, it seems to do a pretty decent job. I’ll keep the household stuff for using in the house, although it does do a good job on the windows in the flat 
I also use Autoglym Fast Glass, does a good job
pound shop, vinegar glass cleaner £1, large spray bottle, brilliant shine, and no harm to bodywork over last twelve months, if that helps, p/s dont tell the wife, its hers.
As being a window cleaner, I use a damp scrim in the shade then go over it with a dry one.
Sunshine causes grey marks and can be frustrating when trying to get rid of them as you often make them worse! lol.
If you run out of all your fancy glass cleaners try using T-Cut. Great for removing tough traffic grime.
Its also great for giving a nice satin-finish to your glass, not really advisable
Auto-Glym Glass Polish (blue label) will do the job perfectly, rain will bead-off nicely but would not advise it is used on a heavily gouged screen as the residue left in the scratches will really show up worse.
Dr. Eunos
Always used RainX, works a treat.
You can even drive in the rain without using your wipers.
Steve