I swore I would never post again but I have to post on this topic. But some info in here is incorrect/misleading..

First, Red does not neutralize Blue. As far as being on the opposite end of the light spectrum, whether right or wrong, its location is irrelevant. It is the color wheel that you have to look at when dealing with color (Not the light spectrum). In this case Orange cancels Blue as they re opposites on the color wheel. To figure this out what happens when you mix Blue and Red? You get Purple.

To this however, Blue is also the largest of all of the color molecules and will be the first to wash out, so if you only left the color on a short amount of time, which is usually recommended on hair pieces, a simple clarifying shampoo or straight dishwashing liquid that you let sit for awhile should remove the blue. However if you left it on longer re-dying it will work. You would actually be better off using a warm Medium brown as the light level colors contain less blue and more warmth (Warm pigments simply do not exist in large amounts in dark colors). By using a brown black you will most likely still have a fair amount of blue in the hair piece (as it is also the first color to oxidize when the color is processing) ...It might work only because of the high dye load, but again you would be better of going a medium brown and letting it sit a bit longer .

You could also mix a little powder hair bleach with both warm water and lots of shampoo and shampoo the piece and it will quickly remove any excess blue.

Just my 2cents after 23 years coloring hair and platform teaching, but then, hey what do I know.