I've noticed that some of my vinyl dolls have gotten a little...dingy? For lack of a better word. But they aren't stained and a couple of spot tests make me think that the issue is the sealant gathering dust, rather than the vinyl itself being dirty. Is there a way to clean this that won't require me to redo the (factory) faceup or damage the vinyl? Normally I'd just very carefully clean around it with W&N and a Q-tip before re-sealing but I don't think doing that every few months would be good for the vinyl
If it's lite dust that hasn't settled in yet, you can try compressed air. Air canister if you can control it or if you have an airbrush compressor, you can dial it to have the air come out softer.
Yes but in my experience they tend to also take off a little of the faceup with them (it's basically sandpaper after all) so I didn't use it very extensively.
Other than those, for some reason the best cleaner I've ever found for stuff other than stains is lotion-free dish soap. A little of it on a soft (or extra-soft, but that won't have quite as much scrubbing power) toothbrush to get into the cracks, and it'll clean just about anything. That said, my vinyl dolls are new enough I haven't had much of a problem with dust yet, so I haven't tried it on vinyl.
I believe the issue is with the sealant. Apparently sealants not designed for plastic will react with vinyl and cause the plasticizer the seep out. Alternatively it your doll was stored for a long time in a box w/ no air, that can also make plasticizer seep out on virtue of it being made of vinyl. I have NEVER done this with a doll head since I haven’t had your issue so take caution. I had anime figures seep out plasticizer due to being old and being boxed for a long time. This made it sticky to the touch. What I did was I soaked it overnight in dish soap + warm water, washed it afterwards, let it dry, and after that it was good as new. If you try this, please be careful if you are working with a head with a custom face up. I believe dish soap should be pretty gentle but it doesn’t hurt to double check.