For those who have never played Nethack, the interesting thing about scrolls, potions, and other magic items was that, when you started a new game, descriptions and spell effects were randomly assigned. So, you could find a scroll labeled JUYED AWK YACC, and later find out it's a scroll of Confusion; from then on, all scrolls of JUYED AWK YACC are Confusion scrolls. Similarly, all bubbly potions do the same thing, all purple potions do a different thing.
What I once did for the rough draft of a game called "Raiders of the Ruins of Kanthe" was create a way to do this during play. At some point, I would like to develop that as a replacement magic system; for now, I'll just describe how a GM could do this with keywords.
Use that ever-useful Random Random Table to pick the first letters of two different words, either descriptive words for potions and magic items, or "magic words" for scrolls. If you'd prefer ready-made descriptions, Risus Monkey has a little PDF of DungeonWords that could be useful, with some adaptation, or you could use my 20-sided Quickies tables in the same way.
If a magic item is supposed to be in this treasure trove, roll for the actual powers of that item and record this secretly. However, you should also place random items elsewhere, perhaps 1 to 6 items in every treasure trove, even if no items are supposed to be in that trove; also place d6-3 items in any room, even those with no treasure. Assign these items random descriptions as well. If a description you've already used for a magic item pops up, that item is also magical; if not, it may be magical; use Zak's random key technique, translating the description into numbers as I described elsewhere; instead of adding the lower of the two numbers to a d20 roll, add it to a 2d6 roll and also add half the dungeon level, round down; if the result is 20+, the item is magical.
Since this will increase the distribution of magic items, you might want to borrow another bit from Nethack and make some items cursed, reversing their effect or target. I'd make another 2d6 roll, but interpret it as a reaction roll; a hostile reaction means the item is cursed. The curse is not connected to the description in any way, so a cursed item can at least help you identify items of the same type. You might want to give items a chance for an additional effect, perhaps an additional spell or a freakish effect using the technique described in spells gone wild, to balance out the fact that the keywords approach makes magic items more easily to identify without the use of a spell.