[QUOTE 4592942, member: 9609"]if vinegar hasn't worked I have had success with petrol, keep it away from the wiper blades though as it will perish them. I would also test on a small unimportant area first in case modern windscreens are made out of something other than glass, also check with the car manafacturer, and obviously take some safety advice from you local fire station.[/QUOTE]
I stand to be corrected but I doubt there are any plastic windscreens out there. Am I wrong?
Anyway, petrol is on the right track, but you would need pure petrol without additives. This is sold in the UK as panel wipe or on some occasions, benzine. (not real benzene, with two Es, which is C6H6). The additives in petrol could just further contaminate the screen.
I agree with your advice to keep it away from the wiper blades but I lament the dire warnings. Surely plain old common sense should substitute for a letter from the car manufacturer and a consultation with the fire brigade.
Anyway.
@meta lon , grease on a windscreen is a problem and whilst I cannot give you the definitive answer, Reiver's advice is on the right track. You need a solvent of sorts. If you have already tried the soapy steel wool option (get pre-soaped pads from Tesco in the cleaning stuff aisle) and still have a problem, it is time for solvents. We just don't know what the contaminant is, so you may have to try different solvents. Obviously you don't want to buy ten different products.
Start with panel wipe. See if you can get a small quantity from a panel beater in your area. I find that if you go prepared with a small container, you can always get small quantities from people. I would also try methylated spirit. Panel wipe is better than petrol because it is pure and evaporates without leaving stuff behind. Petrol leaves stuff behind. Enough so that it cannot be used as a cleaner before painting.
One problematic contaminant is silicone, typically found in ZX-27 - type (make up your own codes and formulas to suit your particular brand) spray oils. Secondly, it is found in dash restorer sprays. The latter usually messes up the interior of the windscreen and that's a bitch to get to.
The trick is to wipe and wipe and wipe, with a clean cloth each time. No use polishing with the same cloth, that'll just spread the grease.
The reason oil, grease and silicone is so difficult to remove from a windscreen is in itself interesting. What you have there is a boundary layer of the stuff. A boundary layer is only a couple of molecules thick and doesn't act like bulk material. It doesn't flow and clings like hell. Water on a windscreen also forms a boundary layer - you can see it when you swipe a windscreen with a squeezee. However, that layer quickly evaporates, leaving the screen clear. Silicone doesn't evaporate and the layer remains. You have to dissolve it with a solvent and then wipe away the solution.This has to be repeated. Then, you have to decontaminate your wipers as well, or probably just replace them.
Good luck.
