I vote yes. I remember the first spring cleaning. I had a phoenix gorget, a phoenix leggings, a black dye tub, and an item bless deed. All really useful stuff back then. I used the item bless deed on a supremely accurate katana of vanquishing, which AOS turned into junk. Not that it had been all that valuable before; I only used it in emergencies, because it would have worn out in a matter of weeks if I had used it every day.
I just traded houses and left about 2,000 pieces of valuable junk I had collected over the years for the new owner of my old house. I had so many gold checks, rares and really nice armor and weapons in the bank that I just had no place to store them while I was moving.
Still, a spring cleaning event would be great. It would get rid of a ton of server clutter and give us something fun to do.
I agree that something like the spring cleaning event should be an ongoing thing, either every spring or just a permanent way to get rid of all the stuff we don't need. Ever since AOS, when monster loot was randomized and the number of items for most of them changed from either zero or one item in a set range, to anywhere from 3 to 30 items, and insurance and pof guaranteed that the stuff we use never wears out, it's accumulated way too fast.