I do usually have a good look at the seat and if stuff bothers me I ask for one of those antibacterial wipes SQ has and give table, some of the surfaces and the remote a wipe.

Out of my last ~10 J flights, sadly I had probably 6 of those where the seat was not properly cleaned by the cleaning staff. I had remaining red wine spill on part of the seat cushion and the left seat panel (A359LH), food (some sort of curry with a crusty potato bit I think) at knee height on the center divider (B789), coffee / cola stain or so on the fold out table, a sticky armrest (B789), etc.

All documented with pics, if it was bad I showed it to the crew and whenever I got the post-flight VOC (voice of customer survey) I marked this part down and explained (not that it mattered or that anyone would have asked about it afterwards ).

So yeah, I wipe the seat and even if it looks clean, you'd be amazed how greyish / blackish a wet wipe can turn when you are done .​