The most aggressive solvent towards polymers, apart from corrosives like acid and alkalis, is methylene chloride. If a 24 hour soak in that doesn't soften it up enough to make it movable, then you are stuck with brute force.
The most aggressive solvent towards polymers, apart from corrosives like acid and alkalis, is methylene chloride. If a 24 hour soak in that doesn't soften it up enough to make it movable, then you are stuck with brute force.