Following up on yesterday's post, here are some ways I think you can make treasure interesting from a "does" perspective instead of an "is" perspective.
Some of these are more sketches than completed ideas - I'm as much thinking out loud as offering solutions. I struggle with this as much as anyone else - my players have more than once disposed of something I put some time into without a second thought.
The key is to find a way to fundamentally change the value of the treasure from its money to its description and use.
Make It Inherently Functional
One way to make a treasure useful is to make it something worth keeping. That's trivial with magic items, but you need to put some thought into it for non-magical loot. An interesting piece of gear can fulfill this sometimes. This is hard, because it usually means it must have some game-mechanical effect similar to magic to be worth keeping. Otherwise, it's just normal gear that is too valuable to risk but isn't any better than a magic item or a mechanically better piece of gear. Even "treated better socially for using this gear" ends up being mechanical or it's better used for money.
GURPS Dungeon Fantasy does this with the Ornate (and to an extent, Silver) prefixes. A +1 Ornate Rapier isn't just worth $3000, but it's also a +1 to reaction rolls for carrying such an ornate sword. Get a sufficiently awesome weapon and shield and suit of armor and you'll be rocking some ridiculous reaction rolls.
Still, "well crafted" just means "more valuable on the market." It might (and probably will) still be sold, but it's got some usage potential.
Clue to More Treasure or More Adventure
This kind of treasure is interesting because it's clearly a way to get more treasure. For example, a hunk of silver is a hunk of silver, even if you pretty it up. It'll get reduced to value and sold. But a silver key? Hmm . . . what does it open? A comb, who cares - but a comb showing men killing those snake-headed dudes the party has trouble with using some special weapons . . . don't sell it, let's keep it around and find someone who knows where those weapons are.
I gave the PCs a brass key once - they put more time and effort into figuring out what it did than they did into caring about the provenance of coinage. I think my notes said something spare, but they interrogated me about the details of the key and I had to fill in the details from my mind's eye picture of the game. It did lead somewhere - it was a non-magical trigger to a magical door - and nearly to a TPK, but also to exceptional loot. Non-magical or not, it was a key and keys open doors. Doors conceal treasures. Offhand, it seems like keys, maps, things that are clearly pieces of puzzles - they add more value if kept and investigated than just disposed of.
One thing I've found useful is to be really obvious tying the clue treasure to what it connects to. A key with a web in the form of a special sigil that's on that unopenable door, a sword with the same logo as that tomb, gems that match the size and shape of the empty eye sockets of a statue, etc. - hey can all point to something bigger. At the least, they reward those who pay attention to something other than the money.
Collect Them All!
A partly-complete set of something might be interesting to players, too - especially if the final, complete set is a) more valuable than the sum of the parts and b) they feel they can actually track down the pieces. Pieces of a rare chess set possessed by a king or something, now its pieces scattered - maybe held one by one by individual monsters, or individual members of some secret magical conspiracy? Hell, they'll search every chessboard they come across and check each piece to see if it's a "special" in disguise. They'll capture random bandits and put their feet to the fire and ask them if they know where the Black King's Bishop's Pawn is.
Sets are even better if they also do stuff, or also lead to a new place.
Sometimes the thing about the treasure is the challenge of turning it into actual value. This is more "treasure as adventure complication" than "technique to convince the players to listen to your spiel." But still, it does make it interesting.
Weight is one way to do this - something valuable, but heavy enough that turning into cash becomes a logistical challenge.
D&D pre-bakes this in with 1.6 ounce coins - enough gold for a suit of mail can run you a few pounds of weight. So enough to really make a serious dent in the cost estimate for a castle can run into the tons. Of course, pack animals and hirelings aren't terribly expensive and cost a fraction of what hauling this away does, but at least it means the PCs need to invest in mules and not just belt pouches.
Still, this just privileges portable wealth like gems and jewelry, and also makes it more likely the players regard it as just money with skippable text because regardless of its "extra" value their real concern is the coinage (and possibly XP, in the right systems) represents.
Size can also make it a challenge. A big statue can be pretty heavy, even if it's only man sized (check here for weight-to-size thumbnails).
Nailing it down means the PCs have to spend some time prying it up. They may ultimately regard it only as money, but if will make them interested in the story of why it's so hard to get at. This includes any and all sorts of traps and guardians, especially if they seem to match the theme of the treasure.
Making the recovery a challenge is also a good teaser for intricate and useful detail on the treasure. Making my players gather coinage one funerary urn at a time (my Barrowmaze homage) certainly made them interesting in disposing of all of the coins but saving a few to investigate further. They didn't seem to think that the passage coins they found were totally unrelated to stone golems and undead ash guardians. It made them look harder at the treasure.
None of the the above are particularly hard to implement - just start sticking stuff like this out there. Don't worry too much about making non-coin treasure sound interesting if it's just going to be reduced to coins and not mean anything even if they do pay attention. If that comb I mentioned yesterday is merely just some nice color . . . odds are they won't care and be quickly bored when they find out it's not a clue.
One approach I haven't tried is a "clues forward" or "clues only" approach. Basically, only give extra description to treasure that has some kind of clue, cue, extra benefit, or whatever. In other words, only describe the special stuff, and always describe it, even if the players don't ask. Do that and you're tell them outright "This is a freaking clue to information, treasure, adventure, or awesomeness. Or it's 1500 in cash. You decide." They still might not care, but that's their decision.
In any case, I think those things make the treasure interesting from a player perspective. From my own point of view running Mirado, the challenges impress me the least and Clues impress me the most. But all of them will make me at least consider writing something down other than "comb, 1500."
I hope this helps, and I sure hope other GMs have some more ideas on how to make things interesting from the player's perspective.