I have no experience with owning a boat with teak decks. I would suggest checking out this forum. Either ask the question or go to the archives.
forums.ybw.com/index.php?forums/practical-boat-owners-reader-to-reader.13/

Or
www.ybw.com/forums/forumdisplay.php?16-Yachting-Monthly-s-Scuttlebutt

Same company.

A good festool rotary orbital sander with 80 then 100 grit ...... ? That would be my choice ....

Thanks for you replies Romona and Sands.

The decks are "au natural" and I don't scrub too often to save wearing them out. The chlorine spillage the other day just highlighted how dirty they have become over the last six years I have owned her. I certainly won't be sanding them but will do something to clean them up.

Surprised to hear that teak is used on the deck of an aircraft carrier.

I have never owned a teak deck boat either Ramona , i,m a fan of the plastic fantastic yachts. that's interesting that you wouldn't sand teak Ramona. I,m not so concerned , timber sometimes deteriorates and needs a tickle up to get the furry bits off.

its sounds like the timber is not coated at the moment , so if left untreated it will eventually dry out and open up , causing bad stuff to happen !

teak is not indestructable , if left it will dry out , open up and get wet...

if it is still smooth enough , and doesn't need a quick sand. I would be at a minimum coating it with some good oil regularly. And considering some-kind of UV protection.

me being a bit lazy though ,would probably choose an oil rub down a 1/2 doz times a year .... and spend the rest of my time considering which UV coating to use....