White stains in gallon glass jugs

[Frognostic]

Last year I bought some used gallon jugs from gumtree because they were cheap.

As can be expected, a lot of them had soiled interiors.

The labels suggested they had last been used in the early 1990s and mid 1980s.

I managed to get some of them clean on the inside and put them to use.

For the rest, I'm talking about 5 jugs not counting the ones I cracked trying to clean them, there remained thin residues of a white substance.

I tried a variety of techniques to get them out including white and red vinegar, citric acid, vwp cleaner, salt water and rice shaken around, soapy water, bleach, I even tried tieing a scouring pad onto a pad and scrubbing it out.

Thing is I could really use them right now.

I'm not sure what these white stains are but I did manage to shift some of them through a combination of the methods mentioned above. It's just some of them remain no matter what I do.

I'm not sure if it's hard water deposits or sick glass pitting but my guess is that it is the mineralised residues of various organic materials such as yeast, mould, plant fibres and the like - possibly turned white by the bleach and vwp cleaner I used.

What I'm wondering is whether or not there is some highly effective chemical for eradicating these kinds of stains that I have not yet used.

 

[Frognostic]

I tried 5 tblsp of citric acid dissolved in 250 ml of water and scrubbing with a scourer on a stick today and initially it looked like I had got the results I wanted.

But when I inspected the glass through a light I noticed the white stains were still there.

Very frustrating.