Answers.Body: <p>There are many things such as dirt and chemicals that can cause elements to change color. Dirt can easily be washed off, but certain contaminants such as cigarette smoke can stain plastic.</p>
  
  <p>The most common issue that causes LEGO bricks to yellow is interaction with ultraviolet light, most commonly from the sun. The simplest way to prevent this is to store parts indoors out of the way of even indirect sunlight.</p>
  
  <p>There are some tips for correcting this issue in <a href="https://bricks.stackexchange.com/questions/83/how-do-you-repair-yellowed-or-faded-lego-blocks">another question</a>, and more details about the chemical process that causes UV light to degrade ABS over <a href="https://chemistry.stackexchange.com/questions/74618/what-makes-abs-plastic-turn-yellow">on Chemistry</a>.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-03-06T05:23:06.297Z
Answers.Text: I don’t think it’s because of light. I kept my minifigures in a locked drawer away from any light (and anything that you mentioned) and they still turned yellow.
Answers.UserDisplayName: Nils The Swedish Yoda
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-03-06T16:19:08.187Z
Answers.Text: Were... were the minifigs yellow before?
Answers.UserDisplayName: RSchulz
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2017-12-03T22:11:00.857Z
Answers.LastActivityDate: 2017-12-04T03:13:07.047Z
Answers.LastEditDate: 2017-12-04T03:13:07.047Z
Answers.UserDisplayName: jncraton
Body: <p>I've noticed that certain LEGO colors have a tendency to turn yellow over time. For example, I have a set of 4 "white" wheel hubs that are all now various shades of yellow:</p>
  
  <p><a href="https://i.sstatic.net/dqQBp.jpg" rel="noreferrer"><img src="https://i.sstatic.net/dqQBp.jpg" alt="8880 set wheels"></a></p>
  
  <p>I know there is already some information on <a href="https://bricks.stackexchange.com/questions/83/how-do-you-repair-yellowed-or-faded-lego-blocks">how to fix this</a>, but I'd like to understand why this happened and how to avoid it. What causes LEGO parts to turn yellow, and what specific steps can be taken to prevent this damage?</p>
  
Tags: <colour>
Title: What causes certain LEGO parts to yellow over time, and how can this be prevented?
UserDisplayName: Jury
ThreadText: # What causes certain LEGO parts to yellow over time, and how can this be prevented?
  
  (Asked by: username_0 on 2017-12-02)
  
  I've noticed that certain LEGO colors have a tendency to turn yellow over time. For example, I have a set of 4 "white" wheel hubs that are all now various shades of yellow:
  
  [![8880 set wheels](https://i.sstatic.net/dqQBp.jpg)](https://i.sstatic.net/dqQBp.jpg)
  
  I know there is already some information on [how to fix this](https://bricks.stackexchange.com/questions/83/how-do-you-repair-yellowed-or-faded-lego-blocks), but I'd like to understand why this happened and how to avoid it. What causes LEGO parts to turn yellow, and what specific steps can be taken to prevent this damage?
  
  **Tags:** colour
  
  ---
  
  ## 1 answers
  
  ### Answer by username_1 on 2017-12-03. Score: 8 | Accepted answer
  
  There are many things such as dirt and chemicals that can cause elements to change color. Dirt can easily be washed off, but certain contaminants such as cigarette smoke can stain plastic.
  
  The most common issue that causes LEGO bricks to yellow is interaction with ultraviolet light, most commonly from the sun. The simplest way to prevent this is to store parts indoors out of the way of even indirect sunlight.
  
  There are some tips for correcting this issue in [another question](https://bricks.stackexchange.com/questions/83/how-do-you-repair-yellowed-or-faded-lego-blocks), and more details about the chemical process that causes UV light to degrade ABS over [on Chemistry](https://chemistry.stackexchange.com/questions/74618/what-makes-abs-plastic-turn-yellow).
  
  > **Comments:**
  > **username_2**: I don’t think it’s because of light. I kept my minifigures in a locked drawer away from any light (and anything that you mentioned) and they still turned yellow.  
  > **username_3**: Were... were the minifigs yellow before?  
  
  ---
  
  