How a Melbourne recycling program is using old hotel soap to solve a global health problem ... A decade after Soap Aid's inception, boxes of used soap from 250 hotels across Australia and New Zealand come to a warehouse in Melbourne's south.

Some soap is yellow-brown, cracked, and filthy. Others are pristine and in their original wrappings.

Phase one includes manually and visually checking, and sorting what is not salvageable.

The rest is checked by a metal detector and scraped clean by hand.

"I check up to 200 kilograms a day," shouts a worker proudly over the whirr of machinery.

Then, soap that is deemed to be reusable is dumped into a machine for a multi-phase process to treat, smash, strain, and then re-mould the soap ...

Mr Matulick said Soap Aid supplied 2.9 million bars of soap to communities in need across the world, including remote and regional Indigenous communities in Australia ...