Irrespective of whether you are cautious AF or clumsy as hell, buying a phone cover for your phone is tech-care 101. 

phone covers
Source: minibay

The trouble however arises when those transparent covers start turning a shade of yellow we're more accustomed to finding inside old Tupperware boxes our moms use to pack sabji

phone cover turned yellow
Source: idropnews

So, if you've ever wondered why your bright phone cover has turned into a sickly shade of yellow, then here's the explanation you were looking for! 

Most transparent phone covers are made of silicone because it's flexible, inexpensive, and durable. However, it also changes colour as it ages. 

old and new phone case
Source: Reddit

And the aging process is fastened when exposed to chemicals, heat, and all the things you won't admit you've dropped on your phone (like the wine you thought you quickly wiped off). In layman's terms, your phone cover turning yellow is a sign of the material degrading. 

phone cover  turning yellow
Source: Ranvoo

However, before you decide to toss out the cover for a new one, try some of these tricks to clean the case:  

Clean the phone cover with a solution of dish soap and warm water. 

Mix two to three drops of dish soap (preferably mild dish soap) with a cup of warm water, and then use an old toothbrush to scrub your phone with the solution. Focus on areas that appear particularly stained, and rinse the cover once you're done. Before putting the cover back on your phone, make sure to dry it off completely with a  towel, and then let it completely air dry. 

Cleaning Phone Covers
Source: WikiHow

You can clean phone covers like this weekly or fortnightly to ensure minimum dust is accumulated. 

2. Scrub the phone clean with baking soda. 

Place your cover on a clean towel, with the side with stains facing up. Sprinkle baking soda on the phone, especially on the areas where the stains are at, and if the stains are tough, feel free to add extra baking soda. Then dampen an old toothbrush with cold water and scrub the case. Ultimately, wash the phone, dry it with a cloth, and then let it completely air dry. 

Baking soda on the phone
Source: wikihow

Baking soda works best for tough-to-remove stains. 

Apply rubbing alcohol 

Dampen a microfiber cloth in rubbing alcohol. A small amount will work, because you do not need to drench the cloth, only dampen it. Move the cloth in circles over your cases, focusing on the area with the stains. Make sure to also reach the corners, before wiping the case with a clean microfiber cloth. Let the case air dry completely before putting it back on the phone. 

Phone Cover
Source: techlicious

Rubbing alcohol also helps in killing off any bacteria, but can cause discoloring in some phone covers. Be sure to do a small patch test (preferably on an obscure corner), before applying it all over the cover. 

If none of these tricks work, then it's time to go shopping for a new cover.