Item numbers can be found by looking at the html frame source of your sell page or your Bank of Nobility contents. Search for the item name; associated with it, either preceding or following should be a piece of code similar to the following (e.g., for the Basic Mining Pick):
<input type="checkbox" name="ids" value="65,0">
The item number is the first number in the value field list (65 above).
It is also possible to map item numbers to items using URL manipulation. The URL http://www.twelvesands.com/main.php?z=13&t=1&l=X will take you to the leaderboard page of the Hall of Records, displaying collections of the item with number X. This works for any item number X which may show up on the leaderboard.
All items (6)