Tarnishing Sterling Silver

I've designed a sterling silver bracelet made from twisted wire and would
like to tarnish it so that it goes black in the cracks of the twists,
similar to the look found on bali silver beads. I've read that the thing to
use is "liver of sulphur". Now, I can't find this for sale in the UK, and
boyfriend doesn't really want me to have toxic chemicals in the house as we
don't have good ventilation. I've also been recommended "Silver Black" by
an American friend, but alas - I can't find that either. Someone else told
me vinegar would work. Now, I can see that it would, as obviously vinegar
tarnishes silver, but how exactly would I go about doing it? Just dunk the
whole bracelet into the vinegar and then polish it up? How durable do you
think this finish would be, and how black should it go? I was wondering if
anyone has any experience before I go wasting expensive wire!

Thanks,

Charlie.