one of my first blog posts. I poked around online to see if such a thing existed, and found this photo of collar clips:
|round nosed pliers, two headpins, thrifted clip-on earrings, length of chain|
Use a type of chain that has links or round rings at each end so you can thread the jump rings/head pins through them to hold them in place. Pick the length of chain you want for holding two ends of a piece of clothing together, and cut the chain if necessary.
Insert the headpin through the hinge opening, thread it through the chain, and wrap the wire around itself to hold it in place.
You are done! Enjoy your new clips on whatever you'd like.
Please let me know in comments if you have any questions or if anything is unclear.
Two notes: 1) Because clip-ons are meant to clasp earlobes, they don't grip very hard, so you can't use them to hold say, a skirt of heavy material up. Sudden expansive movement like stretching (to which I am given) may cause one of the ends to slip off the cloth. You can reduce this some by adding clip-on pads. These will add friction and narrow the clip opening.
2) Experiment with other materials! For example, instead of plain chain, you can try other things. I have this broken bit of bracelet or necklace I found on the street years ago. I think it will make a snazzy chain between a set of clips, once I find some suitable clip-on earrings.
Edited to add: There is such a thing as this! Gracey at Fashion for Giants posted about vintage sweater clips. She went in the reverse direction- she took something to hold clothes edges together and put them on her collar. :D