Diagnosis
The anti-reflective coating on the P-Series Quantum screen is delicate. Using any cleaner with chemicals (even 'screen' cleaners), or too much pressure, will damage the coating and create permanent smears.
How to Fix It
Use only distilled water and a new, ultra-soft microfiber cloth. Lightly mist the cloth with the water—never spray the screen directly. Gently wipe in one direction, top to bottom, using almost no pressure. Let it air dry. For stubborn spots, use a 50/50 mix of distilled white vinegar and distilled water on the cloth, but test it on a corner of the screen first.
If That Didn't Work
If smearing is already permanent from a prior cleaner, you can't fix it. The coating is compromised. Your only option is to live with it or contact Vizio about the panel under warranty, as damaged anti-glare coating is sometimes considered a defect.
Heads Up
Never use paper towels, window cleaner, or anything abrasive. The number one cause of ruined screens on these TVs is someone using Windex. It dissolves the coating instantly.