Refrigerating Clam Juice Most store-bought stock/broth packaging contains some claim like "refrigerate after opening, and use within 7-10 days". My bottle of clam juice makes no claims whatsoever about refrigeration or shelf life. I know it contains some salt, but I doubt it's enough to preserve it indefinitely.

Since it's basically a stock/broth, I assume it would last about as long as an opened container of chicken stock - just long enough for bacteria to establish their own civilization, complete with a "Salmonella Starbucks" on every suspended particle.

Does anyone know for sure? Can I put an opened bottle back in the cabinet? Will it last a week in the fridge? Should I just pour out any unused juice, because it will spoil so quickly?
It should keep in the fridge for a week or two- and you should be able to smell it if it goes bad.  However, you can just freeze any unused juice in 1 or 2 Tablespoon portions (in an ice cube tray) and keep it around for the next time you need it.  Just transfer the frozen cubes into a labelled freezer bag so they don't get lost or thrown out.  Waste not, want not, right?