Opening crimp on factory loads

[bluemike807]

I have a few spare boxes of 7 1/2 trap loads I want to convert to poor man's slugs, with my new Lee Key Slug mold.

Whats the best recommended way to open up the crimps so that they may be safely resealed once I've cast the slugs from the existing 7 1/2 shot?

The factory crimp looks as if it has been melted in place?

 

[tigger]

I would thread a screw in the centre and pull the screw out, and finish opening the crimp with a pen or dowel.