Holy necro Batman! >.< This was a July 2016 thread. :)
Anyway, to leave this here even though it may have been explained before (plus to not make my post completely useless), if you just want to get rid of outfits you cannot destroy and you completely KNOW you won't ever use again, just pay for the smallest premium you can get, or wait for an offer or something that gives premium for a few days for free or something, toss all your non wanted outfits from all your characters into the wardrobe, and forget about them forever.
For example, the starter pack costs around 200 something ncoin (forgot the exact price) and it comes with a few days of premium.You get 400 ncoin for like 5 bucks. Plus the package comes with some in game gold and other goodies. Only caveat is that it can be purchased only once per account.
Well, assuming wardrobe is a level 1 benefit. Forgot that one. Gotta check when the game is back online