Care · 3 min read
Why Do Phone Cases Turn Yellow (And How To Stop It)
Yellowing is a chemical change in TPU plastic — here's what causes it and which materials don't yellow at all.
Clear TPU phone cases yellow because of UV light, heat, and skin oils. The plastic actually oxidizes — it's a chemical reaction, not dirt. That's why cleaning doesn't fix it.
The three accelerators
- UV light: sunlight on a car dashboard yellows a case in weeks.
- Heat: wireless charging + a warm pocket adds up.
- Oils: skin oil and hand cream seep into TPU and react with UV.
Materials that don't yellow
- Printed hard polycarbonate cases (the print blocks UV).
- Tinted or colored TPU — the dye masks oxidation.
- Leather and fabric cases — they age, but they don't yellow.
How to slow it down
Wash the case monthly, keep it out of direct sun when not in use, and don't leave the phone face-down on hot wireless chargers. Realistic lifespan for a clear TPU case is 8–12 months before noticeable yellowing.