The cache is a small sandwich box, you can walk towards the natural pools, you can take a dip (remember to bring a towel). The locals ask for 2€ if you want to use the Grettislaug (laug means pool). Grettir was a famous outlaw that lived in Drangey in viking times, you can read his story online on this website: "http://sagadb.org/grettis_saga.en" or buy the book "Grettis-Saga", the saga was written around 1250. There is also a good text on him in this wikipedia article, goto: "http://en.wikipedia.org/wiki/Grettis_saga"
Once he lost his fire in the island and was forced to swim to the mainland, he used this natural bath to warm him up after swimming from Drangey. Today some pepole repeat this feat. So the locals named the pool after him - Grettispool. Continue towards the beach going north. The cache is close to a large stone bolder!
These stones come from the sand beach by Grettislaug.