recycled silver tarnishing at a faster rate

[joyerico]

Hello,

I have a lot of silver 925 to recycle myself ... i'm taking about pounds and pounds from processing lots of orders ... I use a crucible and a oxy-torch for melting it and then make sheets of the appropiate gauge with my rolling mill. Some borax is poured on the crucible to help into the process.

HOWEVER

i have observed that the silver i got from this process tarnishes faster than the 925 silver i buy from providers ... And i don't understand why... This is really annoying, given i can only use this scrap silver for making samples or oxidized jewelry. And the alloy is exactly the same: 925 scraps put on the crucible and melted.

Do you know why this could happen? How can i fix it?

My guess is that the metal is not well melted and copper doesn't re-mix well with silver in the crucible. Just a gues. No idea

Thx.