Acetate is a forgiving material. It does not corrode, it can be re-polished, and it keeps its shape for years if you avoid two things: heat and abrasion.
Cleaning
Rinse the frame under lukewarm water to lift grit, then wash with a drop of mild dish soap using your fingertips. Dry with the lens cloth that came in the box, not a paper towel or the hem of a shirt, which leave fine scratches on both lens and acetate. For the lenses, a cleaning spray made for coated lenses is fine. Avoid household glass cleaner, which can strip lens coatings.
Heat
Acetate softens above about 60 degrees. A car dashboard in an Indian summer passes that easily, and a frame left there can warp so that the temples no longer sit level. Keep the case in the glovebox or a bag instead. Never try to reshape a frame with a hairdryer; an optician heats acetate evenly in a bead warmer.
Storing
Use the hard case. Pushing sunglasses up onto your head stretches the temples over time; carrying them loose in a bag scratches the lenses. Fold the left temple first, then the right, so the frame lies flat.
Hinges and screws
Hinge screws loosen with use. The small screwdriver on the IRIS LANE keychain tightens them in a few seconds. If a temple feels loose or stiff, tighten or loosen a quarter turn at a time.
Scuffs and polish
Light surface scuffs on acetate can be buffed out by an optician with a polishing wheel, which restores the original shine. Deep gouges cannot. If something is actually wrong with a frame, email hello@irislane.in with photos; every frame carries a six-month warranty.