I've created a query to find posts that misspell Silmarillion or Silmaril. It seems we've corrected most of them now. (I think DavidW deserves a mention here, who has done a lot of these corrections.)
I'll add the query to our compendium of useful queries to keep an eye on any future misspellings, but I would like to expand it a little to include other common misspellings as well.
What other names from Tolkien's Legendarium are often misspelled?
Also, do we want to include missed accents? As wë all know, Tolkíen úses a lot.