I’ve successfully done bleach baths on lace wigs, hair wefts, and various grades of hair. I have not done a bleach bath on thin skin wigs. Thin skin wigs tend to be made out of a material that is akin to plastic. If you have a thin skin wig, be careful. The thin skin might melt or disintegrate due to the hot water or from a chemical reaction from the bleach. I would imagine that you might need to improvise by only dipping the hair in the solution and not the thin skin.