My issue with the silver foot consumable is that it doesn’t last very long and if you use a site of grace to reset your mobs I think it clears it. The silver scarab give much more to the ‘find’ stat I think.
The Magma Blade - so, Volcano Manor naturally. There’s a back-door kind of way to get from the Temple of Eiglay (sp?) site to an area where two Serpent-Men carry those magma blades. The first time through this way you probably headed out the bacony, jumped over, ran up a cliff to the big magma pool and had to avoid an Abductor Virgin by jumping through a window? But from the Temple there’s a side door out to an elevator that takes you in between where the two Serpent Men prowl and bypasses all that. Hope that helps but that’s the best place; quick to reset at site of grace and two to farm.
Blue Silver set; oh yeah, it’s a thing. ;-) Gotta get em all!