Many of these pins are older, reclaimed pins. They range from the 1940's to current time. Membership pins/stars are primarily made from brass and it will tarnish over time depending on environmental conditions. I have found that using a pencil eraser, mainly on membership stars, helps remove the tarnish.
Some will have discs, some won't. If you let me know what color of discs you need, I will supply them free of charge, while quantities last.