Bronze Wool
The suggestion was made to go over corroded spots on vintage trombone stockings with fine bronze wool (bronze wool is preferable to steel wool because it's less likely to mar the remaining plating). And, although, it sounded a little aggressive for trombone slides, it nevertheless introduced the product.
Bronze wool is certainly softer than steel wool and far softer than the chrome plate used on modern slides.
It is a good solution for horns that have darkened pigment under the lacquer which does not come off when lacquer remover is used on it. After the lacquer is off, using the bronze wool does seem to take off that pigment layer.
The use of bronze wool fits in where Steel wool is too aggressive, and metal polish is not aggressive enough.