Just to elaborate on something people may have missed here: All the salvage is in pools, not individual stacks.
All the Common salvage in one pool, the Uncommon in another and Rare yet another.
If you sell a Spell Scroll, someone might be buying that as a Luck Charm, Masterwork Weapon or Inanimate Carbon Rod.
I also happen to think that placing a cap/backstop (at least for a time) on the max you have to pay for salvage will help, and it'll stop the kind of shenanigans that got played with salvage prices back on live.
I can remember those all too well, thanks...