This is an incomplete list of series or bodies of work which are officially free to spoil. Enough time has gone by in enough markets that only one or two humans are left who haven't seen/read it. We feel for them, but not enough to make our wiki look like some sort of weird Swiss cheese.
Spoilers off for:
- If the copyright has expired, or if it predates the very concept of copyright, it's probably free to spoil. In the vast majority of countries, this roughly coincides with anything Older Than Radio. The cat is out of the bag for all of William Shakespeare's plays.
- Anything from myth (e.g., Oedipus), religion (e.g., The Bible), or even legends (e.g., Robin Hood). If it's Older Than Dirt (or at least Older Than Feudalism), it's definitely OK. That said, occasionally spoiling Biblical events (Jesus dies but comes back to life) can be very funny. Just don't go overusing it.
- If you spoiler-tag a fact, something that happened in Real Life, you have our full and express permission to punch yourself in the face. Unless you do it to be funny, then the person who doesn't realize it's a joke and angrily deletes the tag has the face punching permission. Obviously, this only applies if the real facts are completely and absolutely canon: if the story is Very Loosely Based on a True Story, if fictional characters get involved in the historical events (as in Been There, Shaped History, Beethoven Was an Alien Spy, etc.) or if the premise or the setting is Alternate History to begin with, then all bets are off. If a plot twist is based on a reference to a real but obscure event from real life, it would be a Genius Bonus.
- Quotes from a work. Either it doesn't need spoilers, or it doesn't need to be quoted; use ellipses (...) if need be.
- If the article is an episode recap, no spoiler font. The nature of the thing is to give detailed information about the episode. A person who wants both all the details and to not see spoilers is not a person we can help. However, do not add spoilers for future episodes, even under tags. Those go on the later episode pages.
- Foreshadowing is a special case — state only what is doing the foreshadowing, not what is being foreshadowed.
- Fridge, Headscratchers, and the various Moments subpages (Tear Jerker, Moment of Awesome, etc.) are for post-viewing discussions of the work in question - spoiler tagging there defeats the purpose of the articles. You shouldn't be going there if you are worried about them. It's good practice to put a warning at the header as a courtesy to your fellow tropers who may be unaware that they are wandering into unmarked territory.
- Conversely, please refrain from spoiling later episodes/installments in examples for earlier episodes/installments. We want to minimize the Late-Arrival Spoiler effect. Due to its nature, Headscratchers can reference that the issue was addressed in a future episode/installment to close the question in the earlier one, but should not provide details if they spoil said future episode/installment.
- On that note, when a moment in an earlier episode/installment is made Harsher, Heartwarming or Hilarious in Hindsight, made into a "Funny Aneurysm" Moment, or made more clear by a later installment, the respective reaction goes onto the YMMV page for the later installment; the earlier installment should never reference the later one for these reactions. If the event in question is made so by events in Real Life, then it still goes on the earlier work's YMMV page.
- While they may be hidden on the YMMV pages, Complete Monster pages may not have spoilers hidden.
Incidentally, if big blocks of whited-out text (blacked-out text in Night Vision) turning everything into Swiss cheese look needlessly hideous to you, you can set it up so that spoilers are always visible by going to your profile or just by hitting the spoilers switch to the right near the top of the page. You could also check to see if the spoiler text really has anything to do with the trope. If it doesn't, delete it.
If you need to remove spoilers for a whole page, you can use the strip spoilers tool for that. Be sure to add a warning about unmarked spoilers afterwards. Note that it can sometimes mess up potholes within spoiler tags, so it's a good idea to do a search on the page afterward for any stray brackets.