I'm thinking about making a couple of molds so I can recycle my ripped worms.  I was wondering which was better, a resin one piece mold or a plaster 2 piece mold?

be very careful recycling old plastics.  Alot of companies use cheap plastic and put crap in them that they will not repour correctly.

Also heavy salted plastics tend to hold water.  Big no no to remelt plastics with water.

My dad and I have "recycled" tons of old senko's. We used  two-piece aluminum mold and they came out perfect.

My dad has some 25 year old one piece molds but when I pour them they always come out terrible.  I was thinking about making some plaster molds in hopes of making some higher quality worms

For the most part though as long as you don't have super salty worms you shouldnt have a problem