Jessica Sellers no longer accepts Ink of the Sea for lower-level inks. If you want to make, say, the Glyph of Mage Armor, you'll need to mill Outland herbs to be able to make Ethereal Ink. Speaking of that glyph, it's been uncraftable since 4.0.1 and is now available on the trainer. It's going to be a pain to collect mats to make it, however. Still, as one of the more desirable glyphs for mages, it's likely to find buyers, even if Outland herbs are expensive and hard to find.
So what is Jessica looking for these days? Why, nothing other than Blackfallow Ink! It's not yet available in game from any source, so until Dec. 7 when Cataclysm launches. A word to the wise: if you have an herbalist and want to spend a few weeks making cash hand over fist, farm for old-world herbs. Check the "milled from" tab on the following pigments to get a hit list: