I can confirm Craig Smith's comments about how to use Evapo-Rust.
After seeing his write-up in the MBSI's Mechanical Music journal
I found a wholesaler in the UK, and I have used Evapo-Rust on
several organette and piano projects and various other items.

Most jobs will complete in a few hours or overnight but, having
forgotten items once or twice, no harm is done if they are left
a couple of days.  Once the rust has gone nothing else happens,
apart from some minor blackening which is easily cleaned off.
It has also been used successfully used on musical box combs.

I now keep a small stock of Evapo-Rust for sale in the UK and
Europe.  I think I am the only "retailer" in the UK.

John Farmer, UK
www.musicanic.com