Many of my items have 9.25 sterling silver chains, beads and charms. So, I suggest that you use a small silver polishing cloth to care or clean them, gently rubbing the pieces with it, which will remove any tarnish.
With elastic bracelets, I suggest wrapping them in and out of your wrist and not pulling them tightly across your hand. The elastics that I use are very durable, but they are made of an elastic cord and must be placed and removed with care, so that they do not stretch over time.