A magnet will attract the iron weight tips, and lots of the zinc has a Z or Zn on them.
A set of pliers with the wire cutting gap at the jaws will tell you what you have. Good lead WWs will mark easily, while the junk WWs don't mark at all. The pliers work on the stickons also.
The foam rubber and glue will stink to high heaven, but a pot with a lid and some candle wax or a spoonful of used oil, will allow melting of the stickon weights. When you open the pot be ready to ignite the fumes and expect a poooof. Let the flames die and stir well. This brings all the trash and dross to the surface to be removed.
I forgot to mention this MUST be done outside. Burning the smoke really reduces the stink factor, and gets rid of a lot of the smoke.