Can someone please comment on the use of flux-coated brazing materials?  I am seeing more of them in the market. I am also seeing several patents being filed by manufacturers to create better flux-coated materials.  Will this trend increase?  I am familiar of one negative which is the burn off/residue that remains from the plastic used to bind the flux around the allow; however, I think manufacturers are starting to use biodegradable plastics which don't leave any residue.  (at least I see patents for this)