Run the check
Show neutral gray and several solid colors at moderate brightness.
Return to normal moving content and note whether the remnant changes over time.
Consult the display maker's care instructions before using any image-cleaning feature.
Read the result
A mark that fades is consistent with temporary retention; a persistent mark needs maker assessment.
Limits and next step
No browser pattern can promise to reverse permanent burn-in.
Repeat the check after changing one setting or connection. Keep a record of what changed before deciding whether the device needs service.