How to Purify the World in Terraria

One of the most annoying achievements to get in Terraria is “And Good Riddance!” which requires you to have cleansed your world entirely of the world evil created upon world generation, whether that be Crimson or Corruption. This takes quite a lot of effort since these biomes tend to be massive and go from the top of the world to the bottom in Hardmode.

This Achievement is a pain, even if you know the most efficient way to get it, and even if you’re not in it for the Achievement, reaching 100% purity in your ordinary world is also a pain. I’ve written this guide with the primary goal of easing that pain, but do note that no matter what, cleansing everything will always be a difficult process.

Bottom Line Up-Front

To purify the world for the Achievement, your best bet is to beat Moon Lord, convert the Clentaminator into the Terraformer, get Biome Sight potions, and go to town on a newly generated world.


How to Purify the World in Terraria
Image from Monica Phillips.

Before we get started on purifying the world, I don’t want you to think you can do this with a small pile of purification powder and some grass seeds (I mean, technically, you can if you have a few hundred hours to spare), we’re going to need to get the tools to succeed, which means you’re gonna have to go and, at minimum, defeat the Mechanical Bosses in Hardmode.

Doing at least one of these bosses will let the Steampunker spawn (or you can use the CelebrationMk10 seed), and she’ll sell you the Clentaminator for a steep two platinum, but it’ll be worth it. This gun will shoot out Green Solution (that you can also buy from the Steampunker), which will cleanse anything it hits, including the Crimson, Corruption, or Hallowed.

How to Purify the World in Terraria
Image from Monica Phillips.

If you want to go even further beyond, go beat the Moon Lord, then drop your Clentaminator in a vat of Shimmer, which will upgrade it into the Terraformer, making it reach further with its shot, be a wider blast, and have a chance not to consume any solution. This is quite a bit better, but the normal Clentaminator can still do the job.

No matter what tool you’re using, you’ll want Biome Sight potions to back you up. These will highlight any tile infected with the Crimson, Corruption, or Hallow, and they’re pretty easy to craft, with just Bottled Water, Fireblossom, Blinkroot, Moonglow, and Five Grass Seeds. Combine these at a bottle or Alchemy Table, and you’re set.

Going for the Achievement

How to Purify the World Achievement in Terraria
Image from Monica Phillips.

Now that we’ve got our gun and potions on deck let’s discuss the most efficient way to get the Achievement. I’ll talk about how to purify your own personal world a bit later in this guide, but getting the “And Good Riddance!” Achievement is far easier if you generate a small, crimson world that is entirely fresh and go there with your post-Moon Lord character.

Your first directive should be to locate each Crimson biome, with there usually being one on each side of the world, one closer to you and one closer to the beach. Once you’ve found these Crimsons, use your Terraformer to cleanse the surface first and foremost, then go inside the cave and blast it. Now that you’ve got most of it, it’s time for the hard part.

How to Purify the World in Terraria
Image from Monica Phillips.

You’ve got two options, and I’m usually unlucky enough to need both. First is the faster but less reliable method, where you start at the edge of the Crimson biome, then dig a tunnel around it, using Biome Sight potions to guide you and ensure you don’t miss anything while Terraforming. If you see any spots on the map that are completely dark, you probably need to hit those again.

After you’ve done all this, make a few temporary houses, and defeat the Eye of Cthulu, Brain of Cthulu, or Skeletron so the Dryad will spawn. She’ll tell you how good you’re doing on your purification goal, and if she says it’s 0.1% Crimson or around there, try exiting out the world, rejoining, and seeing if she says it’s 0% now. If not, go back and clean up.

You’ll probably have to repeat this step a few times, but if you keep going to the dark spots on the map, blasting them to complete cleanliness with your Terraformer until they’ve been lit up on the map. Biome sight helps a lot here since it can reveal the tiny singular blocks of Crimson you might have missed, and with it, you’ll finish up eventually, getting the Achievement.

terraria cleanse achievement
Image from Monica Phillips.

There is a second, more complicated, but usually cleaner and more consistent method, which is making two block-wide holes that go far down every 185 blocks, then falling down the hole as slow as possible, shooting the Terraformer on both sides, making sure to be as thorough as possible. This guarantees you’re getting rid of the Crimson at the cost of being ugly.

Purifying Any World

Now that you know the process of speedrunning that Achievement, if that’s all you wanted, it’s time to go for the big one and purify any world you want, namely the main world you intend to play on. This process will be incredibly lengthy, and I’d only recommend doing it if you really think you want to play in this world for hours upon hours.

First, don’t down your biome sight just yet, but make sure you have a lot of it; you’ll need it soon. On top of that, stock up on Green Solution because you’ll need a ton of it to purify the entire world with what is definitively the Scorched Earth approach to this, not leaving a single spot blank just in case the evil is there.

tips for the good riddance achievement Terraria
Image from Monica Phillips.

We’ll take a similar approach to the previous, more thorough method. Start at the ocean and dig a tunnel down at the edge, making sure to plug any holes underwater to keep your ocean intact. Burn both sides of this tunnel with your Terraformer, then move 185 blocks inward, and repeat the same steps, using your Terraformer slowly on either side.

This process will tear up your world, take forever, especially in a large world, and only really gets you the satisfaction of seeing the Dryad say your world is entirely pure and not having to deal with a biome that makes your NPCs move out all the time. In my opinion, it’s not usually worth the effort, but it’s something to go for if you care about the world.

biome sight on Terraria
Image from Monica Phillips.

After you’ve set up your holes and fallen through all of them while slowly firing your Terraformer, take another pass down them with Biome Sight on, ensuring you got everything you could possibly see. If you see a glowing tile, shoot it and repeat. Be as thorough as you possibly can because after the Dryad says you’re done, it’s time to clean up.

Patch up each hole using the new materials you’ve gathered, but don’t bother going from bottom to top; you can cheat and fill in the uppermost 50 blocks or so since once it’s far enough off-camera, no one can tell the difference, and no one will care. You should be good as long as there’s a decent amount of dirt and stone covering it.


After all of that, don’t bother patching up the rest of the vertical holes in your world; leave ’em there unless they become a problem. You can prevent any further spread of the Evil biome or the Hallow by just not breaking Altars, not throwing around powders, and not using random Clentaminator solutions. Basically, just don’t be dumb.

You might end up regretting your choice, though. The Hallow is an excellent source of materials used for several crafting recipes, like Fairy Dust and Unicorn Horns, as well as where you summon the Empress of Light or Queen Slime. The evil biomes aren’t anything to sneeze at either, being valuable sources of materials throughout the entire game.

So, if you want to maintain your mostly pure world but also still gain the benefits of these biomes, you’re going to have to make some fake ones. You probably have Hallowed seeds and Corrupt or Crimson seeds left over after you mined quite a bit of the world, so grab those before we get started.

dryad Terraria
Image from Monica Phillips.

You can also put your Dryad in a graveyard biome, and she’ll supply you with some of the opposite World Evil’s seeds, meaning you can have both the Crimson and the Corruption in your world. I’d recommend making these in Floating Islands, as far away from the surface as you can manage without it being too inconvenient or spawning Harpies.

For a Corruption or Crimson biome, you’ll need 300 blocks of evil grass for it to count, and the easiest way to make that is by laying your dirt out in a grid pattern, maximizing the amount of grass tiles you can have. Hallowed biomes only require 125 blocks in total, so you can make that artificial biome a bit smaller if you wish.

Unfortunately, having these fake biomes in your world will cause the Dryad to once again say your world isn’t 100% pure, but having 100% purity is an active detriment since you lose out on the benefits of having access to these biomes. Now that they aren’t spreading freely anymore, you can have them at your convenience without hassle.

Questions and Answers

Question: How do I purify the world in Terraria?

Answer: After you get the Clentaminator from the Steampunker, you can use it to cleanse the world using Green Solution, and placing vertical shafts every so often in the world allows you to achieve 100% purity.

Question: What do I get for 100% purity in Terraria?

Answer: You get an achievement, no more corrupt housing, and nothing else.

Question: Should I purify the world in Terraria?

Answer: It’s not worth it to get 100% purity most of the time; you can create a buffer using incorruptible blocks to protect all your housing and then call it a day.


As much as the game wants you to think it’s something super important you should strive to get right away, achieving purity is a hollow victory since you’ve actively decided to cut yourself out of convenient biomes and features. I know the Dryad stresses you out about your world’s purity, but it doesn’t matter that much.

That said, if I’m ever planning on playing in a world for a long time, purity is an excellent long-term goal, if only so the Corruption stops reaching my housing and being annoying. It’s cool to have a world that you work on for a long while, making it exactly how you want it to be, and I think purifying your world and making artificial biomes are big parts of that.

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