Recycling Soft Plastics

Alright so I'm trying to get into pouring my own soft plastics but I need to know how to add soft plastic hardener to my recycled lures. My friend said you can only use hardener with cold plastisol and I was wondering if I could use hardener on my recycled lures because if you re-melt the lures the get even softer and then and there obviously hot so I can't use hardener I was wondering if someone could help out. And before you hate and cuss at me. I ask please don't do that cause I'm only fourteen so dont expect me to know everything so keep that in mind. You'll probably have to explain for me to understand. Thanks for the help.