Considering the number of elven fallen, where exactly are all of these cemeteries? I know that the Dead Marshes is one such place, but with the gazillions of elves that lost their lives to Morgoth and Sauron (even with lands broken and reformed), you'd think that there'd be some mention of such places in the texts.
Was Hollin such a place? Was it Aragorn that said something like, "The elves have to be gone a long time for the land to forget them," meaning that their dust (beyond their living presence) did something to the land as well.
Me? I'm thinking it's more like in video games where the fallen fade away after some time, leaving whatever artifacts that they carried behind. Great and important (and unusual) persons are 'buried' in the sense that their remains are interred when possible, but for the most part it's just a marker/symbol/memorial for the fallen.
"Here lies Glorfindel the Third,
no bones below will you find interred,
he's gone on the to Blessed West,
leaving behind not but his crest."