OK I worked metal most of my life about 40 years including four years of school..
First WD-40 is great stuff to stop rust but is not a lubricant...
Second I would not use most lubes on my skin..
There are some dry spray lubes with Teflon but to hard to get in bracelet..
What I would use is Mineral Oil /Baby Oil to clean the bracelet I would use Mineral Spirits and soft brush.. You can thin down the mineral oil with some MS as it will penetrate the bracelet more easy..
Penetrating or water dispersing oil like 3-1 or WD-40 and others are not lubricants.. Myself I use nothing other than soap and water every few months to remove the sweat salts from the bracelet..
If anyone need a penetrating oil Kano Labs the best which is Kroil or the aerosol aerokoril
http://www.kanolabs.com/
Let me add WD-40 is NOT a Penetrating Oil.....
It was made to stop Atlas Rockets from rusting it is the 40th formula of a Water Dispersing oil (Anti-Rust) it also works as many other things but not a penetration oil...
Here is the story
http://www.wd40.com/about-us/history/