If an object is melted down , it is heated until it melts, so that the material can be used to make something else.
Some of the guns were melted down and used to help build a statue...
When Jefferson didn’t like a pair of goblets given to him as a gift, he asked a local smith to melt them down...
Some thieves do not even bother to melt down stolen silver for its scrap value.
PHRASAL VERB : be V-ed P , V n P , V P n (not pron)