Q. Can you polish silver items during the 9 days? is it permitted even for weekdays use? Can you ask a domestic helper to do it?

A. Nitei Gavriel (Bein Hametzorim 1: 28: 17) permits polishing silver items during the Nine Days, since in principle only washing clothes or creating new vessels is prohibited.
Horav Shlomo Miller’s Shlit’a opinion is that when in need it is permitted also for weekdays. When possible a Gentile domestic helper should do it.

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit’a