is it possible to "Un-crimp" a shotgun shell?

Hey guys, I'm wondering how all these people load there shotgun shells with exotic shot, such as, airsoft bbs, glass:taped:, m&ms:thumb:, etc

I've got a few ?s...

How do they empty out the shot?

Do they just recrimp the shell after they have loaded the shot?

is it possible to "Un-crimp" a shotgun shell?