Old 1/32 Pyro Car models questions.

Hi All, I finally scored a few 1/32 Pyro vintage car models; these are the same ones I was given by my uncle when I was about 8 years old. They bring back lots of fond memories of sticky glues and missed meals. I have these questions: 1. Does any of you know what kind of plastic these were made out of? What modern glue should I use on them? I test a piece of sprue with Tamiya thin cement: modern model plastic would meld, or show visible effect on contact with the cement, yet the piece of sprue seems to be impervious to the glue. I finally get 2 pieces to bond, but the bond is very weak, pliable and easily broken. What should I do? 2. They also include gold plated sprue: these plated metal can be removed (I tried with bleach on a piece of sprue), but they leave behind a tough, semi transparent material which, again, seems to be impervious to modern Tamiya thin glue (they don't meld or stick at all). Again, what modern glue should I use on these? 3. The instruction mentions using "polystyrene" cement. What is the modern equivalent? What brand should I use? Any help on these matter is greatly appreciated. Many thanks.