So as I was in disassembly of my Kadett and got to the trunk and the fuel tank. When I took it out it raddled like rocks were in it. I know that was a possibility because when I was a kid you put rocks in the tank of people you didn't like. Back to the story, I emptied out the tank of the noise and I found the below. A bunch of lead buttons/balls that were flat on one side and domed on the other with a letter "W" or "M" on them. Now they could have been a discontinued Lead flavored M&M's that went out with red dye #5 but I just don't know what they were used for.
I search the web and some say that back in the 60's some put lead sinkers in their tank when the gas gauge broke and when the the gas was low they would rattle. Others said was when unleaded fuel came out some put lead sinkers in their tank to "supplement" lead additive. The aluminum solid cylinders are a mystery to me too. Anyhow, let me know what you think.