Here's another card that might not make it through the mail if it were sent today. It has a little cloth bag of salt attached as a souvenir from the Great Salt Lake.
There's some very faded printing on the bag that says Great Salt Lake. The postcard photo shows people disembarking from open-air curtained train cars, with the first Saltair Pavilion in the background. The pavilion was built in 1893 and burned down in 1925. A replacement was built, but it also suffered from fire damage in 1931 and then burned down completely in 1970. Although a third pavilion was built, it was plagued by various problems, including unpredictable water levels. In a good year you might be on the edge of the water, but the next year might be a different story.
You can see by the back of the card that moisture has wicked out some of the salt.
Here's a close up of the text on the back.
The Salt Lake is also a valuable habitat for birds. Here's an earlier post on bathing at Saltair.