Why not simply sell the useless metal and get the money instead?

Why on earth central banks keep the useless metal I'll never know.

No useless metal enclosures between air and heatsinks.

Shrogh was a fairly useless metal, difficult to alloy and too heavy to be helpful in the construction of space vessels.

It had been fused into the same mass of useless metal.

It's a relatively useless soft metal that is a by-product of our mining operations.

For a moment he balanced the lump of useless metal as though to hurl it directly into Daneel's face.

By which time there was a new interest in the previously useless metal.

Makes use of the strange properties of some otherwise quite useless metals.

Little bricks of a particularly useless metal - no more.