Etsy's Definition of a Treasury:
The Treasury is a member-curated gallery of short-lived lists of 12 hand-picked items each (plus four alternates). It functions as a high-demand (and pretty!) promotional tool that many devoted Etsians fight to get. Members can feature their favorite items, items selected on a theme, or just however they like. The Treasury is not intended for self-promotion, but instead to acknowledge and share the many cool things for sale on Etsy. Admin often choose an exceptional Treasury list to promote on the home page and occasionally make them to tie into Storque articles or special events and occasions.
The Treasury will open to new lists when the number of total lists is below 333.
To see when that will be, sort the treasuries by Expiration; then count back.
When list 333 is close to expiring ~ Do Not Click the Refresh button!
Instead, click the treasury page number.
Sometimes it can take upto 10 minutes for that expired list to actually drop off of the lists. Wait Paitiently. Do not close or refresh. The only thing you can do is click the number. Turn on your sound, it makes a noise when a treasury is deleted or drops off of the list.
When it drops off this is what the boxes will look like.
Type in your title, be quick the boxes will disappear.
Remember to click 'Create'
To fill your treasury, get the Listing Id's from items.
Type or Paste them into the boxes in your treasury.
Once it is filled, you can rearrange the items.
Treasuries are usually 2 days, a random number of treasuries are lucky and last 3 days.
If you create a treasury and it won't let you fill it; exit out of your browser and try to go back in. On rare occasions, you will not be able to add any item numbers.
When there are a lot of treasuries created at the same time, occassionaly some will dissapear for a short time or for good.
For more Information view the Storque Article.
Newbie Advice on Creating a Treasury by Winklepots.
Visit Etsy Treasury to view current treasuries.