Guild Wars 2

Maybe u bought more than one salvaging machine and now with shared slots u only need one.
Maybe u bought a pickaxe and now u would prefer sprocket pickaxe…
Maybe u bought the dance book and now u are bored about it.
Then:
Unused items puchased with gems would be salvaged to get a reward…

Salvage into what? What reward?

Sorry, you made the purchase, you’re stuck with the result.

Anything to compensate the purchase of an expensive useless item

Your post isn’t very informative. Salvage to what? Mats of some sort like 2 soft wood logs? Gems?

If mats, why should they do that? Delete the item and go to a map and do some harvesting.
If gems, you’re asking for a partial refund of a purchase. They’re not going to do that just because you bought something and then a long time later got bored with it or whatever.

joseanjim.8096:

Anything to compensate the purchase of an expensive useless item

Maybe a half of its value in gems
or Spirit Shards
or Stones of Mystic Forge
ANYTHING

Just contact support. Maybe (just maybe) they will give you a refund.