Use them for “item use” event.
Item useJust because they're useless to you doesn't mean they should be tossed. So much goes into other areas of development, why waste their time trying to remove items based on levels of progression. I'd rather have then keep working on new content and champs! Area these items annoying to max players, yes, but they can be dealt with easily.
Once a player hits level 60 these xp boosts should be a gold boost instead. I end up popping all mine at once from inventory screen for item use event and that's all. So disappointing to open dailies or other crystals and to open something totally useless.