An option for those multiparts which have a threaded metal insert cemented in the pinhole. You want to display it on a pin but can't. You can do the acid and wait method, as I have done many times. But what if you do not want to do that, or what if the insert is not cemented but instead is set with lead. Pretty much nothing dissolves lead so your only option is to drill it all out. Good luck with that.
I have inherited an older multipart that I do not want to mess with. I have used this method in the past, but today I remembered to take a couple pictures as I went along.
Quite simple really. I do not know much about the different pins but for the ones I find locally with the lead threads, this works just fine.
With a zip disc in a hand grinder, I cut around the base of the threads and then cut up and over the top, much like a MLOD. Do not cut all the way through as you want to leave the threaded end of the bolt intact. Then using a flat screwdriver, just pry the lead halves apart and remove. Clean the threads, add a bead of weld around the pin to the base to stabilize everything and you are good to go.
10 minutes tops vs a month or two with the acid.
In some cases the threads are the same size as the insert and the insulator threads right on. In most cases the bolt is a size small and the multipart just slides on. Not perfect but then neither am I.