Board Thread:LotR Mod Technical Support/@comment-29253515-20200115163047/@comment-26222246-20200115205745

If you remove those your world will most likely get corrupted. If you can figure out how to use world edit with lotr mod block ID's (I think it's possible, judging by other builds, but I'm not sure how it's done) and use the //replace command over an area to replace all the blocks with the intended block.