And Good Riddance! - Guide to Getting 0% Corruption/Crimson

A guide to help players get 0% corruption and earn the "And Good Riddance!" Steam achievement.

Introduction

The 1.4.4 Labor of Love update added a lot of new things to Terraria. It also added what might be the most difficult achievement in the game: "And Good Riddance" which is attained by reducing the Corruption, Crimson, and Hallow in a world to 0%.

It may seem impossible. You equip your Clentaminator and purify every block you see.... yet the Dryad keeps telling you the world is still 1% corrupt! Is she lying? Is she keeping a single block of Crimstone in her dresser drawer to screw with you?!

Probably.

But it's not impossible, and this guide will tell you how to do it!

Requirements

So first off, what are the actual requirements for the achievement?

Simply, the reward is for having the Dryad tell you that your world is 0% Corrupt, Crimson, and Hallow. I'll say that again because it's actually important: the achievement is not actually for getting 0% Corruption, the achievement is for having the Dryad tell you that the world is 0% Corruption.

This means that you will need to have the Dryad in your world, meaning you will need to kill a boss, build a house for her, and have her move in, then talk to her, select "Status" and have her tell you the level of Corruption/Crimson you have.

Of course, this does also mean you'll have to actually have 0% Corruption in your world, and this is the hard part. So, here is what actually counts:

• All Corruption blocks, including Ebonstone, Ebonsand, and Corrupt Grass, as well as walls. This includes both naturally occurring and player-placed.
  
• All Crimson blocks, including Crimstone, Crimsand, and Crimson Grass, as well as walls. This includes both naturally occurring and player-placed.
  
• All Hallow blocks, including Pearlstone, Pearlsand, and Hallow Grass, as well as walls. This includes both naturally occurring and player-placed.

And here is what DOES NOT count and therefore does not need to be worried about.

• Altars DO NOT count.
  
• Shadow Orbs and Crimson Hearts DO NOT count.
  
• Flesh blocks, Ebonstone Brick blocks, and other crafted blocks DO NOT count.
  
• Demonite and Crimtane ore DO NOT count.
  
• You DO NOT need to be in hard mode. (And it's easier if you're not.)

Getting the Achievement

Now that we know what we need to do, let's get this achievement! Here's what you'll want to do, in order:

1. Get the Clentaminator and Green Solution. They're sold by the Steampunker NPC, who moves in after you've defeated at least one of the mechanical bosses in hardmode. If you've beaten the Moon Lord you can toss your Clentaminator into the Shimmer and transform it into the Terraformer, which will do this even better... but that's not really necessary.
   
   And yes, technically you can do this without the Clentaminator, as long as you have a Nightmare/Deathbringer Pickaxe (or better), Purification Powder, and/or Explosives... but this is NOT RECOMMENDED. The Clentaminator will make your job 1,000x easier. If you don't have the money or haven't beaten a hard mode boss yet, then you should just put this achievement off for later.
   
2. Create a new world to purify. This isn't strictly necessary, but will make things much easier. I suggest a small world, Crimson (which is easier to purify compared to Corruption), and no special seeds.
   
3. Optional: Get a world previewer. This isn't strictly necessary, but is highly reccomended. The reason why is because your world may have small patches of world evil in random places apart from the sections you can see from the surface. For example, when I did this, I had two Crimson biomes, and then also a small patch of Crimson that spawned underneath a pyramid far away from either of my Crimson biomes. I would not likely have found that on my own if I didn't have a world previewer. Personally, I recommend TerraMap (terramap.github.io). It works online so you don't have to download anything to your own computer, and has a feature to highlight Crimson/Corruption blocks so you can find them easier.
   
4. DO NOT FIGHT THE WALL OF FLESH. This should go without saying, but I'm saying it anyway. Right now your world evils are small and there is no Hallow. Entering hard mode isn't necessary and will only complicate things.
   
5. Fight a boss to get the Dryad to move in. You'll need her to give you the seal of approval and the achievement. All you need is to defeat a boss. Any boss will do, and since you'll be going into the Crimson, breaking Crimson Hearts and fighting the Brain of Cthulhu is a good way to start. Then just build some simple little box houses until the Dryad shows up.
   
6. Start purifying. Find your world's Crimson (or Corruption) biome(s) and get to work. Start on the surface and walk along, spraying the Clentaminator into the ground as you go, then head underground, spraying outward through the ground. Try to maintain a slow and steady spray with your Clentaminator, getting every block you can. If you just spin around wildly, then you'll be likely to miss some spots. Also, spray directly into the ground, not with the ground. Small bits of evil may be just behind the surface of the ground and you want to get them all. Once the biome is purified, search the surface and make sure there are no additional Crimson biomes.
   
7. Talk to the Dryad. Select the "Status" option so she'll tell you how much Crimson/Corruption you have. Hopefully she'll report 0% and the achievement will pop. If not, then check your map previewer again (if you're using one) for anything you might have missed. Return to your evil biome(s) and head through them again, spraying the Clentaminator slowly through them again, making sure to get absolutely everything you can. Remember, that background walls count too, and it's possible there's a wall you missed behind a dirt block or something. You may also need to quit and reload the world to make her update her status.
   
8. Repeat the last step as needed. It may take a couple of passes, but eventually you'll get it.
   
9. Enjoy your new achievement! Or don't. Don't let me tell you what to do. I'm not your mom.

Purifying an Existing World

This guide assumes you're going to generate a new world solely for the purpose of earning this achievement, however I will also give some tips on how to purify an existing world.

1. Use a map previewer. Again, not necessary but highly recommended, and again I recommend using TerraMap.
   
2. Dig hellevators through the map. For the uninitiated, a "hellevator" is just a 2-block wide hole going all the way from the surface to the underworld. A hell elevator, if you will. You'll need a bunch of these, no more than 120 blocks apart, through your entire map. Will it look ugly? Probably. Will it be a lot of work? Absolutely. But this is the price you pay for purity.
   
3. Start purifying. Using wings or better yet a flying mount (Broomstick, UFO, or Pirate Ship) travel up and down the hellevators, spraying your Clentaminator or Terraformer to the sides as you go. Maintain a slow and steady spray, getting every block. Repeat until you've done the entire world.
   
4. Remember the map extends beyond your playable area. The edge of the map where you can no longer walk or see is not actually the end of the map. It goes past that quite a bit and you'll need to spray all of that too.
   
5. Congratulations! Your world has been purified! Now to go outside and touch some real, non-pixel grass!

[spaze]

@Knight9910 i was just playing with my friends on our multiplayer server and asked the dryad the status of our world and she said we didnt have corruption nor hallow, I didnt even know that you could cleanse those back then. It's 100% some kind of bug, didnt play any workshop map

[Knight9910]

@spaze - You probably loaded up a custom world off the workshop that already had it. Aside from that, I couldn't tell you.

[spaze]

why did i get this achievement even though i didnt do anything

[Knight9910]

@Gill_The_Wolf - Remember that background walls also count. That could be the issue.

[soup.iam]

Does anyone know if Crystal shards that were grown on pearlstone count as Hallow

[Knight9910]

@Spirit_OK - Will do!

@EaBoi - No one ever said it would be easy. <w<;;

[Spirit_OK]

TerraMap says "no Crimson set blocks", Dryad says 1%. Any advice?

UPD: got the achievement after reloading the world. You may want to add this step to the guide.

[EchoFort]

losing my mind with em 1% hallow and crimson and my world looks very ugly too