Need Help Removing Chalky Sealant from Dark Tan Resin

Oof yeah, it looks like you've got everything going against you here! In my experience, 1. Dark resin is the only resin this happens to, 2. MSC is the worst offender, and 3. Alcohol is the least helpful to clean it

I mostly use W&N liquid brush cleaner to wipe dolls, and while it is still harder to get dark resin clean, you can tell that you're making progress and eventually the cloudiness is gone. With alcohol I always felt like it never got clean no matter how much I scrubbed.

In the future, I'd avoid using MSC on dark colors. It's just TOO matte. Sealants that have a tiny bit of sheen work better, so I think you'll have better luck with Testor's. I use Volks ZM Powder Finish and it works well, too.

If the cloudiness really seems like it's in the resin and NOT leftover sealant, let the resin throughly dry and there's a chance a new layer of sealant will make it disappear. I can't explain it but it has happened to me

 

I don't dilute the brush cleaner, but I do clean the parts with dish soap when I'm done, because it can leave behind a residue. Also, definitely do not soak resin in the brush cleaner, because that can make the resin soft and easy to dent.

Good luck!

 

So had a similar issue with the chalky look with my resinsoul dude when I got him (not as bad in the picture, but he had some patches) and I figured it was a finishing issue since i'd never had a doll so dark before. I didn't bother trying to clean it and I just put some satin varnish on him and it did the trick for me. (my logic was how gloss finishes fill bad sanding, and it was going to be my next attempt if the satin didn't do the trick)

I use the liquitex varnishes cause I like I can use it without it becoming airborne particles. never tried the other stuff before.

 

Overlordu already said a lot of good things.
I own quite a few darker skinned dolls, so I know the plight too.

First of all: using a cotton ball is NOT scrubbing That's wiping at most. And to really get off sealant you need more elbow grease. I can assure you that lighter skinned dolls were probably not fully clean when you wiped them, but their skintone often hides it well.

What I do to get my darker dolls clean:
- magic eraser
- 90+% isopropyl/rubbing alcohol
- regular rinsing with water
Unless you rinse it off with water while the alcohol is still wet on the surface, you basically will just keep pushing the residue around and let it cake on again. You need to actually get it off the doll.
Rinse and repeat, literally, a couple times and you should get the doll pretty clean again.

Also, yes, sealing then helps to hide some of the blemishes too. My non-sealed heads always look worse than the sealed ones
No idea why. But I had a lot of Iple dolls that suddenly got visible sanding marks once I started cleaning them, that were not there before when I got them from Iple. Once sealed the head was even again.

In regards to the sealant: MSC is indeed infamous for it. In my case I tend to use the one from Citadel for the majority of the faceup, and only use MSC at the end for the finally step (cause I like its tooth and strength more). I also give my dolls a semi-gloss finish as final layer, because it looks more realistic and helps reducing the ghosting effect.
The Zoukeimura Finishing Powder is apparently a good alternative too. Airbrush also tend to fair better (if you have an airbrush).

Also, check out this resource. It touches on some things you asked (for example, search for “My sealed parts look lighter all of a sudden, how did this happen?“) : THE BIG BJD FAQ

 

No one has said this yet, but I'm removing MSC from a darker doll at the moment, and Dawn dish soap in water? Works if you just soak it?

I was going to wash some brush cleaner off, and didn't have time but didn't want it to dry, so I put the face plate in to soak and promptly forgot about it (thanks, ADHD). When I remembered it, the sealant was coming off en mass. It's been about a month now of moving it from dirty water to clean water and lightly scrubbing with a toothbrush in between, and I'm down to the little bits deep in the ear and lip grooves. It's not fast by any means, but I'm not able to scrub hard and don't mind the wait.