Ahh, you found me... Run!
All spells go in the same pile (middle one I think) of the first row.
Spells are all the cards where the art covers all the card, i.e. there is no black border.
Smelt gold is a "normal" card, so it goes in the big market stack.
There are only five types of cards that go in the top row:
1) Beer (including the war mug big beer).
2) Scrolls (all of them have a picture of a scroll).
3) Spells (all of them have art on the whole card).
4) Potions (healing and the big healing potions).
5) Nuggets (all the cards are the same).
Everything else, shuffle into a big Market stack.