Chosen Solution

So short story I’ve had my SE in the case since 2016 and I decided to take it out to clean it. I’ve realised the pattern of the case is basically integrated into the back of the phone. I’ve tried scrubbing it for like 15 minutes but nothing changed. Is there any way to remove it? TIA

Okay, so with this scenario, it appears that the case did damage to the finish on the housing. You could try to polish it, but the best choice would be to do a housing swap, or put the case back on, as it will hide the marks.