I watched a YouTube video on how to crimp alligator clips. The method the guy used worked great. Strip the end of the lead, fold the wire back over onto the insulation, insert into the back of the alligator clip (like the one Thomas shows in his post) until the wire is all inside and then crimp. I assume the crimped area will eventually come loose, but the alligator clip will almost certainly be destroyed by then. Just cut off the old clip and replace with a new clip.