Polishing is cosmetic and safe to do whenever the finish looks dull or covered in fingerprints. A string change is a convenient time because you can reach under where the strings normally sit.
Steps:
- Remove the strings or slacken them so you can reach the whole top.
- Dust the guitar with a dry microfiber cloth first. Wiping grit around can leave fine scratches.
- Spray a small amount of polish onto the cloth.
- Wipe one area at a time: top, sides, back and the back of the neck.
- Buff with a clean, dry section of the cloth until the surface is clear.
What to avoid:
- Household cleaners: they can dull or damage guitar finishes.
- Paper towels or shirts: they cause fine scratches.
- Polish on bare wood: on an unfinished fretboard, polish seals the surface. Use oil instead.
- Polish on strings or pickups: keep it to the finish.
S.I.T. makes its Guitar Polish (GP-4) in our own plant, and sells the Premium Microfiber Polish Cloth (GP-PLC) and the Guitar Polish with Cloth Kit (GPPLC).