Um piss off. It is not irrelevant or misinformation. That is exactly what petroleum is.
You clearly can't understand a factual statement from an opinion I never said it was good I never said it was bad I just said it was. If you'd bother to take a moment to think about it. You would realize that I was referring to the fact that petroleum is extremely energy dense. For the very reason I stated. That is fundamentally why petroleum has become a successful energy source and why it's been so difficult to replace.
You're welcome to point out where I said it was renewable. I think you're going to have a difficult time finding that statement.
As for being a pedantic ass that's clearly your territory. A pedantic ass that it likes to put words in other people's mouths.
This is the best plastic epoxy I have found. JB Weld plastic weld. There are others if you can't get it.
So take it apart. Clean it especially if there is any soap. Let it dry. After it is dry it might not hurt to do a light clean with rubbing alcohol. Then epoxy it back together, per the epoxy instructions. This type of epoxy is very noxious. Do it outside and leave the top outside for a few hours. It is also best to not touch it, use a stick.
It really depends on the type of glass some glass transmits UV light and some types reflect UV light. And that is not taking into account the pile of other factors that will affect it.
Citric acid is commonly used in the canning process. So look in the canning section of the grocery store. The last time I found it was at an ACE hardware that had a very good canning section.
Oxalic acid is an option for rust removal, but it is less common. Basically you need an acid that is safe for fiberglass tubs but works on rust. I have also used stuff like CLR or Lime-Away. Just double check that they are safe for the tub.
Just remember that even weak acids can be dangerous to work with. Wear gloves, eye protection and make sure the room is well vented.