Flotsam & jetsam!

There's a simple mnemonic that helps distinguish flotsam from jetsam. Flotsam (or floatsome) are those items which are floating as a consequence of the action of the sea. Jetsam are those which have been jettisoned by a ship's crew (although that may float too of course).

http://www.phrases.org.uk/meanings/flotsam-and-jetsam.html