Slot for Armor Storage
You might consider buying a character slot and storing them on that one. I had several mules in Guild Wars 1 that I used only for storage of various items. The other alternative, is to get a guild bank to use as storage. Iirc, it costs about 8 gold to reach the 50 slot bank. The problem with it is you can’t store account/soul bound stuff there. However you can store other items there and free up storage in your bank for bound items.