thisplace.com.au - Removing Lacquer from Brass

The answer to this question is fairly easy - use paint stripper.
Stripping lacquer is really no different than stripping paint from furniture.
Just go to your local hardware store and pick up some good quality paint stripper - if you are not sure just ask one of the staff - then it just a matter of following the directions on the back of the product.
If the piece you are going to strip is solid brass the paint stripper won't cause any damage - however if it is plated brass over steel you will more than likely strip the brass finish as well.
Don't confuse lacquer thinner with paint stripper - once the lacquer has dried - the lacquer thinner is no good.