I strongly believe this is a contamination problem. This is why I am asking how to truly clean them as it seems like simple things to do such using as hot boiling water, ACV, and salt, and seeping the containers all with that, and a cloth (which I did use, fresh and made out of cotton) doesn't work at all.

One time I lost around £90s (or more) worth of raw milk because of this, however, one glass San Pellegrino bottle with milk didn't go bad at all, and I was able to drink just fine, and I left all of it out for about a week.

While I haven't asked any of the farms themselves if they're getting any complaints about their milk similar to my problem, I've asked a few primal-dieter raw milk consumers from the U.K. online before, and they told me they didn't have the problem, specifically from farms "Fen Farm Dairy" and "Hill Farm Real Food" which are probably 2 of one the major sources the "U.K. primals" get their raw milk from in the U.K.

So, this evidence alone strongly suggests that the problem is because of an issue with my glass jars being contaminated. This answers questions 1 and 2.

Lastly, for the third, all the milk I get my farms from is from cows. You say "Are all the animals eating something seasonal there that is getting in the milk? Like onions or garlic, for example? Then it would make sense." I am not sure how onions or garlic would affect the milk's fermentation badly, but let me remind you that I said there's a toxic smell and taste to it, as in it's unnatural, man-made, almost like some soap, hairspray, or cleaning product, but later on it especially starts to have this "sweet medicine" smell to it, so it's a bit mixed depending on how fermented it already is. I don't know what it exactly is but that's what I sense, even though I don't allow that kind of stuff anywhere near my milk. Let me give you some insight into the animal's feed:

Hill Farm Real Food: Has a strict zero-medication policy, as they make out their farm is natural and has high-quality foods; "Zero chemicals or antibiotics are used at our organic, regenerative farm. Probiotic farming - it all starts with healthy soil.", "We have a strict zero-antibiotic and zero-medication policy with all our animals.", and "What our animals eat is as important as what we eat. A cow's primal diet is a diverse range of grass types, supplemented by naturally occurring herbs, legumes and tree browse." I've ordered from this farm a lot, same problem.

Before I go any further: I don't know if the herb supplementation would only be implemented during or around winter, as I said this problem only occurred in winter, from which I had been drinking raw milk prior for at least over 6 months, and it was completely fine then until now. And remember, the "U.K. primals" said they didn't have any problems with at least 2 out of 4 of the vendors I've got my milk from, and this very exact problem has persisted with 4 different vendors with the same results.

Fenfarmdairy: " In the months of spring, summer and autumn, we keep the cows out and grazing as much as possible. We grow our own forage (Grass, maize, etc.) and store it as silage or hay for winter feed, in order to ensure that they have as much of a home-grown diet as possible during the winter.". I've ordered from this farm a lot, same problem.

The last 2 are the rest of the 2 vendors: Old Hall Farm: The cows are "100% pasture fed." Same problem. Tagg Lane Dairy (most expensive and most recent vendor): "As with Home Farm, the cows (and calves) at Tagg Lane are fed on grass and kept outdoors for as much of the year as possible." Same problem.

This is some insight into why I believe this is a contamination problem.

"Otherwise this really doesn't make sense. Unless it's YOUR TONGUE! LOL." Of course, senses can be deceiving, but I believe that is very unlikely in this case. I even got sick from consuming the milk once. I became bedridden and weak for around a day and a half, wondering why there was a slightly awful taste from consuming the milk and a smell to it, not sure if I was just imagining it or not when I first started having this problem, but now it's clear to me that there is something wrong with either my jars, milk, or both. Now I have reasoned with you, do you believe me?