Umm...
According to the piece "bronze disease is caused by chlorides and oxygen combining in a damp environment..."

And the cleaning advice is to use 'salt and water'

Salt is Sodium
Chloride and water is H2O so definately contains oxygene as does air and definately damp !!

LOL
Weird advice :D :D :D
Just a thought, but is the piece actually
BRONZE metal ? or is it
bronzed resin?? Most of the Border Fine Arts pieces I've seen are resin-based and not actually metal ;) In which case I'd simply give it a good dusting and use a soft hair paintbrush to clean the finer detail - which is what I do with my 'bronze' African figurine :)