@ Zeldafield - Posts cannot be deleted, only hidden. Hiding 19 pages of posts would be very time consuming, not to mention that hiding of posts is usually reserved for posts that are breaking the forum rules. Hidden posts still take up the same space, only with a "The contents of this message have been hidden" message instead of the original content, so that would not make the thread more useful for you to make additions to.
Instead. it would be better if you created a brand new thread, with the reserves that you need, and then post back here to ask us to close the original thread.