Getting a full card of buttons is always a thrill. Even a partial card of buttons is a great find. However, the cards they come on are not always such a treat. In fact, 100+ year-old cardboard that's been exposed to too many elements can be down right disgusting. Like in the top picture, some are rusty, moldy, or crumble at the slightest touch. Others will surprise & delight as much as the buttons with their charming artwork.
I found a very nice lot of hidden gems. These are mother-of-pearl with cut steel escutcheons and brass with cut steel facets & escutcheons. The gems were hidden under a lot of rust, but after several hours of scrubbing with a bit of elbow grease, metal polish, steel wool & dish soap, the majority were salvageable.