Soldering nuggets

Was: White gold cracking

Lead, tin, or some contamination may have sneaked in and it
only needs the tiniest bit... It will boil and sputter
if there is contamination and then calm down when the contaminants
are burned out. Worth a try, you may be surprised! 

I believe this operation is working but extremely dangerous because
you turn the metal in vapours and risk to inhale them?

On the same note anybody has an opinion about soldering nuggets?