How can I get the film off old Mason jars? They have been in my father-in-laws cellar for several years. I have tried soaking them in Lime Away for a week. I scrubbed them with Comet. I even soaked them in soapy water. They still have a film on them. Any suggestions would be great.
They probably have what is called "etching". It's usually caused by washing in the dishwasher - usually from soft water & too much detergent. This will not come off. So you either have to live with it or buy new jars. Sorry.
I would try soaking them in a mixture of borax and hot water.
Or try soaking them in soapy water with a little ammonia. Leave the house while they soak. If they are etched, this will not help. By soapy water, I mean regular dish detergent, preferably Dawn. It gets out/off a lot of stuff other soaps won't.
If the film is on the inside, try denture cleaning tabs.
You might try Barkeepers Friend, don't know if it'll work or not, but it's worth a try. Also, there is a product at the auto store to clean headlights - but it's probably made for plastic. Depending on the emotional value, it'd probably be cheaper to buy new jars.
I'd try vinegar if you haven't already. But the denture cleaner, as one mentioned, seems like a possibility too.
Soak or scrub with acetone. Outside. If that doesn't remove it nothing will.