
Yep, I said it..."tidy."
Etsy admin does use treasuries with sold items in the collection for the front page. They also use treasuries that are days/week old. However, they will put an alternate in place of the sold item. Since treasuries do not expire and if you don't delete your own then you should consider keeping up with the sold items. I generally check mine once a week and choose to delete some and then replace the sold items with new items from the same shop.
I have noticed in many of my treasuries that one to five items have sold in a very short time. If five have sold you will not have enough alternates to cover the ones sold. Good reason to keep an eye on those rascals!
There is also a bug in treasury making. Some people have found that if you use an item for your treasury that has a number in the title, either that item will not show up, or one of your other items will not show up. It doesn't always happen, but a pattern has been observed. If you have numbers in your titles, you may want to consider taking them out so that people feel safer using your creations.
Clicking and commenting is still important for treasuries. Doing this helps keep the treasury you made on the first page of that huge list. I've seen one of my treasuries stay on the first page for an entire day when it got plenty of comments and clicks.
So, get those brooms and dust mops out and clean up your treasury!