How to reduce tarnishing - Handling
If tarnishing is a big worry to you, use clean white cotton gloves when you handle pure silver coins / bars to reduce or prevent the oils on your fingers from staining the coins. This is how professional jewelers handle the diamond and gold jewellery. Tweezers with plastic tips are also good tools to pick up the coins with.
When examining your coins, lay them on a clean surface or on a piece of clean lint or velvet cloth to prevent the coins from picking up contaminants.