I have a head that was sealed properly with 3 layers but when removing the faceup, the eyeliner inside the eyes does not go away no matter how much sealant or thinner is used. It's only inside the eye, not on the face. The eyeliner on the face removes perfectly fine. What do I do to remove the eyeliner left in the eye? I am against sanding it because this is a very tiny BJD and sanding it could make that area too thin.
If I understand you correctly the area that's stained was not sealed because it's inside of the head? If you must remove it try a melamine sponge, it's a very fine grit abrasive and should take some elbow grease to take away a noticeable amount of resin, so if it's not working, you can stop before you do any damage. If it's just paint stuck on the porous surface then the sponge may be enough to pull it off. I would not recommend any stronger solvents if you're worried about thinning the resin.
Yes even though I sprayed a lot and did many layers, I guess under the top of the eye/inside the eye did not get sealed. Thank you!!