Charles Spurgeon Commentary Isaiah 40:19-20

"The image, a workman hath cast [it], and the goldsmith overlayeth it with gold, and casteth [for it] silver chains. He that is too impoverished for [such] an oblation chooseth a tree that will not rot; he seeketh unto him a skilful workman to set up a graven image, that shall not be moved." — Isaiah 40:19-20 (ASV)

The workman melts a graven image, and the goldsmith spreads it over with gold, and casts silver chains. He that is so impoverished that he has no oblation–

No precious metal.