Your fins are your in water means of locomotion. Unlike car engines, fins need very little in the way of care and maintenance.

Care & Maintenance of Snorkeling Fins That Have Been Stored
Inspect the foot pocket area of the fin for any cracking or signs of dry rot. If you have strap fins, inspect the areas nearest the buckles. If the strap does show signs of dry rot, it is best to replace the strap as soon as possible and make sure that the buckles of strap fins are functioning correctly.

Care for Snorkeling Fins During and Prior to Transport
If not already done, follow the instructions for fins that have been stored. Conventional fins can be quite difficult to be packed in carry on luggage for air travel and does weigh more. Whereas the Travel Ready fins have shorter blades and better lend themselves to packing in a carry on luggage. To view the Travel ready fins, look for the Trek Fins, Shredder Fins and the SplitFlex Fins. Click on Snorkeling Fins.

Care of Fins During Multi Snorkel Days
If possible, rinse your fins in fresh water between snorkeling ventures to lessen salt water crystal formation and to remove any dirt buildup. Keep the fins out of direct sunlight as much as possible.

Care of Snorkeling Fins Prior to Storage
Thoroughly inspect the fins following the same procedure as "fins that have been stored". Soak the fins in warm soapy water using a mild liquid dishwashing liquid to break down any salt water deposits and dirt. Use a soft bristled toothbrush for hard to reach areas. Thoroughly dry the fins and if you have any food grade liquid silicone such as Seal Saver, put a few drops on the rubber portions of the fin and using a clean dry cloth, work the silicone into the rubber. Let the fins sit for an hour or more to allow the rubber to absorb the silicone. Wipe off any excess before storing. Store the fins in a cool dry area away from direct sunlight. Make sure that any rubber portions (usually the foot pocket and/or strap) are not in contact with any silicone as this will cause premature discoloration of the silicone material itself.