I had some time and a hot-melt glue gun.
Two pincushions were made simply by cutting circles of fabric, running gathering stitches around the edges and drawing the gathering stitches up around balls of hobby fill. I added a dab of glue to the containers and then shoved the gathered balls into place. I sewed the ribbon or ricrac into loops (and sewed the ‘fake’ bow on the red and white ribbon) before gluing them into place too.
I thought about using hobby fill to stuff the jar’s pincushion, but I could not get it to stay away from the edges of the lid. I decided I needed to make a bag to contain the stuffing, and in that case I might as well use crushed walnuts as stuffing instead, as they have a nice weight and feel.
I still have three more little op-shop containers to convert, but they need a bit more thought – measuring and calculating – to make pincushions that fit.