I started picking at the wicker covering and it was not coming off easily. I gave up and let them sit on the porch for a while. Finally, I ordered some outdoor-friendly fabric to cover them. The base was a bit of a mystery, but I finally just decided that spray paint wouldn't hurt it so I went for it.
They are currently hanging out next to our cart. They can be pulled into the sitting area and used as a seat or footstool, or they can be pulled up to the table and used as another seat.
Not bad for $15 worth of fabric and a can of spray paint we already owned.