I'll never use any plastics in making any products period.... Even water in plastic transfers so during a chemical reaction that's a big NO NO for me...
What about distilled water for your soaps & other products, which most of us need to use? Usually packaged in plastic. What about product shrink bands, fragrance oils (the chemicals used to make them can sometimes be found in these too), product packaging, plastic lined cardboard tubes (which I have opted for as it greatly reduces the amount of plastic I put out there myself)? What about the buckets & bags we all receive raw materials in? What about business cards & product tags / labels coated in plastic? What about the computers we use to access this forum, find suppliers & other info? Not to mention the microprocessors / chips / cables / modems etc which allow us to access the internet?
The solution is not black & white, and there is no one right way of doing things. For me, the important thing is to minimize their use myself whenever possible, in the products we purchase, the equipment we use, as well as the products we make - including the same chemicals used in plastics which can be found in many other raw materials, such as fragrance oils, preservatives, you name it. That's one of the reasons I choose to do a lot of research regarding the raw materials I use in my products. How are they made? What's in them? Do their ingredients or processing negatively affect our wellbeing, as well as the wellbeing of other living things, and our planet? Are there better alternatives? 9 times out of 10, there are, and we have the freedom to choose those alternatives.
I absolutely get the fact that plastic is a bane in so many ways (in reality, it doesn't have to be), but the fact is that it does have its uses. That said. we have become far too reliant on plastics (made from petrochemicals) there are far better ways to make them, with far fewer toxins, which emit significantly less disease causing filth into our air, soil, water etc. Manufacturers also need to make a concerted effort to make plastics which are more stable when in contact with other substances, as well as more readily biodegradable than they currently are. Suppliers also need to make a concerted effort in using less plastics, or less toxic ones. And we need to start demanding that corporations are taxed heavily when using plastics to package their products, rather than the many other viable alternatives. At the moment, WE are taxed for the billions of pounds of plastics in our environment, and their recycling / clean-up, rather than the billion dollar corporations adding to this global mess. Personally, I would rather pay a little more for a product which is responsibly packaged, packed & shipped, instead of having more 'environmental taxes' jammed down my throat which ultimately are not being used for any environmentally positive purpose.
Good on you for wishing to minimize your plastic use, but I hope you can also understand that being militant about it isn't going to help any of us, or this earth we live on, or the living beings sharing her with us. Militancy often makes us blind to all the ways we ourselves are contributing to the problem. Making logical, responsible choices, and openly discussing them with others, is what will help us turn this show around.
I hadn’t realized glass could actually explode from lye
but is that due to a rapid change in temperature? Or somehow the “etching”?
I use thick glass because I’m terrified of accidentally knocking over the container and spilling whatever is inside. This happened to me several times with the plastic containers I eventually use for making smaller batches, but fortunately that was always in the sink and the soap had already reached trace.
The glass is also nice to see what’s happening at the bottom; I’d otherwise miss it if a lye-crust had formed in a plastic container.
Regarding microplastics, yeah, it’s not great if they’re dispersed in the environment. I guess the specific plastics that don’t react with lye at all aren’t going to be a problem, but I don’t know enough about chemistry to identify such plastics.
Now I’m not sure what to do…
Putting your lye container into a stainless steel pot or other type of vessel can easily prevent accidents. if it cracks / breaks, the lye will be contained & you can easily go on about your business. If not, no problem
That IS a LOT of money spent, but I hadn't thought things through well enough at that stage 
- is not something I'm ok with. Those 'miniscule' bits add up to many thousands of dumptruck-loads, yearly, that are killing everything, including us. I regularly gather this stuff from the little cove near my house, loads of it, so I get to see & feel what a huge issue plastics are in real time. It disgusts me, so if there's something which I can do to mitigate this situation, I feel I have a personal responsibility to do so. I'm using my stainless steel canner for mixing soap batches now & large Pyrex measuring cups for my lye mixing. That also allows me to see how well things are dissolving, as you mentioned 
